Gone Nuclear
by Aini NuFire
Summary: Did Crowley know that giving Cas that second stolen grace would trigger a chain reaction to rival a nuclear time bomb? Probably not… AU after 10x3. Major hurt!Cas
1. Chapter 1: Back to Normal--Or Not

**A/N: This story is dedicated to Miyth, who wanted to see a h/c bunker!fic with Cas's stolen grace going haywire. Hope it lives up to your expectations! Thanks to 29-pieces-of-me for beta reading. ^_^**

 **Disclaimer: I don't own** ** _Supernatural_** **. Also, several lines will be lifted from various episodes throughout the season(s); don't own them either.**

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 **Chapter 1: Back to Normal…Or Not**

Dean pulled the Impala into the bunker's garage and killed the engine. He and Sam had just finished three days straight of nothin' but R&R on a lakeside beach, knocking back cold ones, watching people on jet skis, and just overall pretending there was no such thing as monsters, demons, angels…or the Mark of Cain. It'd been good. It'd been relaxing. It'd been…boring as hell.

Dean got out of the car and went around to the trunk to retrieve their bags. Sam followed silently, and Dean was doing his best to ignore the look of concern his little brother kept piercing him with. If he didn't acknowledge it, maybe Sam would let it go.

"How you doing?"

Or not.

"Golden, man." Dean slung his rucksack over one shoulder.

"Come on." Sam angled that annoying puppy dog mien at him.

"Seriously, I'm good. I am." Dean hefted Sam's bag out of the trunk and then slammed it shut. "Taking some 'we time,'…best decision we ever made." And it _had_ been good. Not that they had spent their vacation recreating a Dr. Phil show and talking about their feelings and how they'd really screwed up lately. They'd just made a silent pact to put all that crap behind them and go back to being brothers. Getting away from the bunker for a bit had also been a good idea; a lot of bad memories there were still too fresh. Like, 'oh, that's where Kevin died,' and 'that's where Dean tried to kill Sam with a hammer.' Yeah, wasn't it great to be home?

Sam reached to take his own luggage, but Dean pivoted away.

"Dude," Sam protested. "My elbow's fine now."

"I thought it was 'more than a sprain,'" Dean parroted from one of their conversations on the beach.

Sam rolled his eyes. "Yeah, but giving it proper rest helped a lot." He lifted his arm and rotated it as evidence.

Dean started carrying both bags toward the inner door. "I got 'em anyway."

He and Sam entered onto the balcony level of the bunker and shuffled down the stairs to the war room, past the Commodore 64, and into the library. Both of them stopped short on the threshold, brows lifting with incredulity. It looked like librarians on parade had decided to re-catalog everything by first taking half the books off the shelves. Two of the four study tables were stacked with old, hardbound volumes, while a third had an array of tomes laid open with tabs and sticky notes inserted between various pages. The fourth table had a large piece of butcher paper rolled across the top, each corner held down with some random object: a mug, a pen holder, an onyx sphere that was either an actual paperweight or a crystal ball, and a book on fairies. Haphazardly sketched notes and thought bubbles were scrawled across the paper, linked by arrows, things that were crossed off, and lots of question marks.

Dean shook his head. "Okay, this is the last time we leave Cas alone with a bunch of books. He's worse than you."

Sam ignored the jibe. "Cas?" he called.

"Sam?"

The brothers turned as Cas emerged from the rear hallway, three more books stacked in his arms. These looked ancient, bound with animal hide and hemp stitching. The angel walked in and set them on one of the tables, having to scoot one of the piles over a little to make room. Dean watched a tower of tomes on the opposite end come precariously close to the edge.

"I didn't hear you return," Cas said. "Did you have a good time?"

"Fantastic," Dean replied absently, stepping closer to the paper to scan its contents. "Uh, what have you been up to?"

"Researching the Mark."

Oh, right.

"Find anything?" Sam asked.

Cas let out a frustrated sigh. "Not yet. The Mark is just so old, it predates the lore. But I haven't given up," he added quickly. "There's still a lot to go through."

Sam arched a brow at the numerous stacks. "Have you been at this nonstop since we left?"

"The sooner we find a cure for the Mark, the better for everyone," Cas replied. "I told Hannah I couldn't help with any more rogue angels until this was resolved."

"Bet she loved that," Dean muttered. He wouldn't forget how the bitch-angel wanted to stick his head on a pike out of 'principle.' At least Cas had told her no.

Sam shot him a slightly peeved look, even if he did feel the same about that particular angel. "Uh, would she be able to find any answers in Heaven?"

Castiel's eyes darkened for a second, and then he shook his head. "I already asked, and no."

Dean frowned, suspecting there was something Cas wasn't saying. But he didn't want to call the angel on it right then. He was taking his time, getting back to normal, being zen. Okay, not really the last one, but he'd fake it till he made it if he had to.

"You shoulda said you'd be sticking around this long," Dean said. "We would've set you up with a room."

"I don't require sleep at the moment."

At the moment? What happened to angels don't need sleep at all?

"That because you're all juiced up on coffee?" Dean picked up an empty mug that had several brown rings staining the inside at different levels, suggesting multiple refills.

Cas shrugged. "I've come to appreciate the taste."

"Great, we're gonna have the Energizer bunny with wings running around."

Cas canted his head with an almost flippant, yet tense air. "I don't have wings anymore, remember?"

Dean waved a dismissive hand. "You know what I mean."

Castiel gave a small head shake. "Yes, well then, I believe I should get back to it."

"Let me unpack and then I'll come help," Sam said, eagerly taking his bag from Dean. Sam strode down the hall toward the bedrooms while Cas slid into a chair at one of the study tables, leaving Dean standing in the doorway. Maybe he should join them in the research. After all, the Mark was on _his_ arm. But he was trying to 'take it easy,' and dammit, he didn't want to dive back into this crap just yet. He wasn't a demon anymore, wasn't feeling the bloodlust like he had been. He was _fine_.

Turning away from the stacks of books, Dean headed for his own room where he put on some headphones and tried to drown out the world and all his problems in a cacophony of drums and jamming guitars.

Dean could say everything was okay, put on an air of casualness, pop open a bottle of beer, and kick back as though he had not a care in the world. But come night, dreams tore down those flimsy facades and left Dean exposed and bombarded to the truth and all its horror. In sleep, the Mark stirred, painting his dreams with images of blood and carnage. First with monsters and demons, those that deserved it. Abbadon. Metatron. But then the scenes shifted, and Dean was no longer the dark knight, but the very creature he feared—black eyes and blood stained lips. Bodies ripped to pieces sprawled around him, and Sam's terrified face staring up, pleading, as Dean lifted the First Blade and prepared to…

He bolted upright in bed, a cold sweat making his shirt stick to his damp skin. Chest heaving, Dean whipped his gaze around the small living quarters, the guns decorating one wall, his mom's picture on the writing desk. He was home in the bunker. He was fine. Everything was fine.

And yet, Dean couldn't shake the tremors that ran through his muscles, or swallow the hard lump in his throat. He scrambled off the bed and for the door, wrenching it open and charging down the hall to Sam's room. Pausing to steel his nerves, Dean grabbed the knob and slowly turned it. The door clicked quietly, and he eased it open a few inches to peek inside. An abnormally long lump was settled on the bed, one leg nearly dangling off the side. Dean held his breath until he heard Sam let out a soft snore, and only then did he allow himself to breathe. Sam was okay. Dean hadn't done the unthinkable, the one thing he could never fix.

He stayed a few seconds longer, watching his brother's seemingly peaceful sleep. At least one of them could do that. Dean closed the door without a sound and then slumped against the wall, running both hands down his face. He wouldn't be going back to bed. Returning to his room, he checked his phone for the time. 4:30am. He considered going out to the kitchen and putting on a cup of much-needed coffee, but he didn't want to face an interrogation from Cas on 'how he was doing.' So he grabbed a change of clothes and a towel, and headed for the communal bathroom.

He stayed in the shower until the hot water ran out. Sam would probably be pissed later, but Dean almost hoped for that, for the normalcy of brotherly bitching, rather than the surreptitious glances and well-meaning but irritating questions. He stood in front of the mirror now, staring at his reflection and finding his own expression as questioning as those of Sam and Cas, as though the man gazing back at him was someone else, someone who could give him answers on how to fix the shit-hole he'd dug himself into. One Dean stared in silent desperation, the other in stoic defeat.

His eyes dropped to his forearm where half of the reddened, puckered scar peeked out from his sleeve and stood out starkly against pale flesh. Dean may not be a heartless demon anymore, but the Mark was still working its sinister influence on his soul. He could feel it, in every breath he took, like a dormant, torpid pulse waiting for its moment to break out again.

Dean tore himself away from the mirror. Taking it easy wasn't helping as much as he'd hoped. No, he needed to get back to normal, back to hunting. All Dean had to do was convince Sam that he was ready.

He reached for the switch to flick the lights off when the halogen bulbs started flickering with a low buzz. For a moment, Dean froze. No matter how many times he'd seen this phenomena, he was still floored. This wasn't supposed to happen in the bunker; it was warded! And it couldn't be Kevin this time, because the kid's spirit had gone with his mom, attached to his father's ring. So there was no way a ghost could be in the bunker again.

Dean stepped out into the hall and inched warily toward his room. The lightbulbs in the corridor hummed, followed by the high-pitched echo of Dean's stereo in his room going on the fritz. Adrenaline shot through him like an injection of liquid fire.

" _Sam!_ "

The door at the end of the corridor swung open and Sam barreled out in flannel pajama pants and a white t-shirt. He frantically swiped unkempt hair from his face as he whipped his gaze around. The lights continued to drone out a disturbance. "What the hell…?"

"Bunker's haunted again," Dean muttered, even as he felt a secret thrill of excitement. _This_ was what he needed. Well, not some unknown monster invading their sanctuary, but hunting something? Oh yeah. He started heading for the weapons room.

Sam scrabbled to keep up with him. "No, that's impossible. I mean, it can't have been an old Men of Letters, or they would have reappeared before now. And it can't be…"

"Yeah, not Kevin," Dean agreed, pushing open the door into the armory. The Men of Letters had lots of interesting weapons: blades, maces, samurai swords. Dean snatched up an iron-plated axe.

"Dean, just slow down. Did you talk to Cas?"

"Why would I?" Speaking of which, why hadn't said angel warned them of a ghost lurking about? Dean turned toward his brother. "You think something happened while we were gone? Man, if Cas brought someone here and they died, I'm gonna kick his ass."

Sam threw his hands up in front of Dean. "That's not what I meant, and I don't think Cas would do that. He knows how secret this place is."

"Okay, then we're back to unknown ghost." Dean grabbed a shotgun loaded with rock salt and shoved it into Sam's arms.

Sam rolled his eyes. "Or maybe Cas found a spell or something to help with the Mark and is experimenting."

"If that's the case, then I still oughta kick his ass for waking you up." Dean hefted the axe and pivoted to head back down the passage toward the front of the bunker.

" _You_ woke me up."

"Yeah, because there's a ghost."

Sam's mouth moved in a silent sputter as he hustled to keep up, and Dean felt a smidgen of smug satisfaction at making him speechless. The lights had stopped flickering, but that didn't mean the intruder had left. Ghosts could linger in the Veil without always manipulating physical surroundings.

Sam finally shook his head with a sigh, shifting the shotgun into a ready position. "You feel any cold spots?"

Dean shrugged, eyes peeled for a wisp of specter or scintillating air. "No. You?"

"No. Let's just find Cas and see what he says."

What else could it be besides a ghost? Still, they'd have to search the library at some point; why not first? No other electrical equipment started going haywire, and Dean began to wonder if maybe he'd just imagined it, or perhaps this old bunker had what Charlie called 'techno gremlins.' Too bad she was in Oz and not able to come help them out with it…

They reached the library, all of its light fixtures in standard working condition. Cas was sitting at the same table he'd been at last night, as though he hadn't moved at all. His head was currently in his hands, and it was difficult to tell if he was reading the tome in front of him or resting. Dean once again had the fleeting stray thought about angels not needing sleep, but he was more focused on the potential ghost.

"Cas," he called, a little surprised the angel hadn't heard them enter.

Castiel looked up, blinking as though he had in fact been caught dozing. His brows rose at the weapons they carried. "What's going on?"

"There's a ghost flitting around the bunker."

Sam let out an exasperated noise. "I don't think it's a ghost."

Cas frowned, and quickly stood up as his narrowed gaze swept around the room. "I thought this place was warded against anything supernatural getting in."

"It is," Dean said. "So did you invite a friend here for a sleepover and forget to tell us?"

Cas's mouth thinned. "No. And I haven't left here since before you two did. Could you have brought something back with you?"

"Not me." Dean angled a pointedly questioning look at Sam, who merely glowered at him and turned back to the angel.

"I thought maybe you were experimenting with a spell or something for the Mark."

"No, I haven't found anything like that." Cas paused, tilting his head in that considering mien of his. "I don't sense anything either."

"Well, let's take angel radar here and do a sweep of the place," Dean said, gesturing with his axe for them to chop-chop. Man, he hadn't felt this excited since…well, his time as a demon didn't count. No, he was the good guy again, hunting down the things that lurked in the closet or under the bed.

Sam looked like he wanted to argue, but even he couldn't just ignore that _something_ was screwy here. Cas, on the other hand, appeared more ready to jump to their aid, and he strode purposefully around the table toward the main room. As he brushed past one of the support columns, however, the bulb in the wall sconce suddenly exploded, spraying fiber glass back at Dean and Sam.

Dean jerked to the side to shield his face, and then swung the axe up, ready to take a swing at the briefest wobble of air. Sam also had the shotgun up and braced against his shoulder, eyes wide and searching. Nothing moved. Nothing flickered like an old VHS tape. The temperature didn't plummet. There was _nothing_.

Sam blinked first. "Uh, Cas? Was that you?"

Castiel stood rigidly next to the pillar, eyes boring a hole into the shattered light fixture.

"Aw, hell," Dean said, lowering his weapon. "It was you the whole time?" Dammit, he'd really been hoping for a case.

Cas canted his head at Dean, then back at the glass bits sprinkling the floor. "I…suppose so. Sorry."

Dean scowled. "No more caffeine for you. We don't need a wired angel wreaking havoc with these old systems."

Cas's mouth tightened into a thin line, and he ducked his gaze.

Sam's brow furrowed with concern. "Cas, are you okay?"

"Fine." He rolled his shoulder in discomfort. "Perhaps I should take a walk, get some fresh air." Turning with a swish of his trench coat, Cas headed out of the library and toward the stairs.

Dean let his axe-head clunk on the floor with a sigh. "So the bunker isn't haunted." He probably should have tried harder not to sound so disappointed.

Sam's eyebrows scrunched in distaste. "Dude, that's a _good_ thing. You seriously wanted some crazed ghost running around?"

"I wanted a case." Dean shook his head morosely and started to leave, calling over his shoulder, "You know, normal!"

Except, 'normal' for the Winchesters usually involved some major crisis that threatened all of humanity, so maybe he really should have been more careful about what he wished for…


	2. Chapter 2: Control Issues

**A/N: Thanks to all the follows, favorites, and reviews! ^_^**

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 **Chapter 2: Control Issues**

Sam cut through a tomato, squirting juice and seeds over the plate and his fingers. He gave the knife a dirty look. Slices, how hard was it to make neat, clean slices? He wasn't trying to _kill_ the tomato after all. With a heavy sigh, Sam let the kitchen knife clunk on the counter. He kept seeing Dean wielding that battle axe with barely contained excitement. It wasn't anything like the look in his brother's eyes when Dean had been a demon and stalking him through the bunker with a friggin' hammer. But…it stirred up the memories nonetheless. And Sam had to wonder just how strong the Mark's influence still was, even after the sanctified blood had successfully purified Dean.

Sam didn't regret taking a few days off with him, getting out and going somewhere to relax. But it was time to get back to work, specifically back to finding a way to get the Mark off, before Dean started going off the reservation again. Which meant Sam would need some brain food, so he picked up the knife and resumed trying to cut thin, non-slushy slices of tomato for his sandwich. He'd make one for Dean too, even if his brother would pick the tomato off.

Footsteps drew Sam's attention over his shoulder as Cas entered the kitchen. The angel gave him a brief nod while striding to the sink, where he grabbed a glass and filled it with water from the tap. Cas leaned back against the counter, practically gulping the entire cup down. Sam found himself scrutinizing Castiel's appearance. He looked pretty good. Clothes no more rumpled than usual, though it was kinda strange seeing him without the tie. There weren't any dark smudges under his eyes like there had been the last time Sam had seen him, shortly after Dean disappeared. Overall, Cas seemed perfectly fine, so there was nothing for Sam to be concerned about. Except for the weird electromagnetic interference…

"Hey Cas," he said, clearing his throat. "Are you sure you're okay?"

Cas set the nearly empty glass on the counter. "I'm fine, Sam. You don't need to worry about me."

"Well, I do. I appreciate how gung-ho you've been about researching the Mark, but Dean and I are here now to help pick up some of the slack, so maybe you should scale back a bit, take care of yourself."

Cas shook his head. "The Mark isn't like anything we've ever dealt with before. There's no telling how long it will take to find an answer, or where we might have to look. I need to help you both as much as possible while I still can."

Sam frowned. _While he still can?_ "Maybe we should also be searching for a way to deal with your stolen grace," he suggested in a slightly lower voice.

"Dean and the Mark are more important."

Sam pursed his lips, an uncomfortable knot coiling around his gut, because yeah, part of him felt the same. The past few months had been about nothing except finding and saving Dean. But saying it was because Dean was 'more important' than Cas…well, that didn't sit very well with Sam for some reason, and he started to feel guilty for not having tried to help the angel with his problem before. Even now, Cas was putting the Winchesters above himself without question or hesitation. But, Cas _was_ mostly okay. Yeah, a few stray lightbulbs going pop was disconcerting, but nothing monumental. Dean and the Mark was just a more _urgent_ situation at the moment.

Cas refilled the glass with more water, and then started to leave, but Dean entered the kitchen, blocking his exit.

"Hey guys, hope you weren't talking about me," he said blithely, though Sam detected the defensive undertones.

"Actually, we were—"

"Discussing research priorities," Cas interrupted. "There are a variety of approaches we could take—focuses on demonology, Biblical accounts, or curses in general—and we should probably divvy them up."

"Riiight," Dean drawled in response. "Actually, I was thinking Sam and I should get back to hunting."

Sam straightened, the kitchen knife once again clattering uselessly on the counter top. "What? Dean, it's only been a few days."

Dean spread his arms out to the sides as though on display. "A few days of complete relaxation and recuperation, and now I'm good to go."

"You don't need to push yourself, Dean," Cas said.

"I'm not made of glass!" He let out a growl of frustration and began to pace. "Seriously, you two don't need to treat me as though I'm this fragile thing that's gonna break the minute I encounter a monster or pick up a weapon." He shot Sam a pointed look that made the younger Winchester wince. Sam didn't think that. He was just…worried. He hadn't missed those times when Dean's gaze would go slightly distant, and drift down to his arm where the Mark hid just under the long sleeves. Dean wanted to pretend nothing was wrong, but he wasn't fooling anyone, not even himself.

"Is this about the Mark? Is it making you want to go out and kill?"

"No, Sam, jeez!"

Sam crossed his arms. "Well, remember what you said about the Mark needing to be fed? If you're not feeling that now, then why go out and hunt and risk triggering that hunger again? Right, Cas?"

Cas reached up to pinch the bridge of his nose. Since his stint as a human, he'd picked up a lot more mannerisms, which Sam would have found amusing any other time. Though in this case, Cas actually looked more like he was developing a headache rather than just expressing exasperation. Dean had a knack for eliciting either reaction from people, even angels.

"We could just do something easy," Dean pressed. "Like a run-of-the-mill salt and burn."

"Look," Sam said, desperate to get his brother to see reason. "I just got my arm out of the sling."

"You said it was fine."

He scowled. "It _is_ , but that doesn't mean I should risk a repeat injury so soon." Not that such an excuse had ever stopped him in the past, but this time he'd play that card for as long as he needed if it kept Dean safe at home.

"Fine, I could go by myself. Just a small hunt, somewhere close."

"What about researching a way to get the Mark _off_ you?" Sam was trying very hard not to lose his patience here; didn't Dean see how important this was? Ignoring the Mark's effects had gotten them into a shit-load of trouble already; they weren't going to make the same mistake twice.

"Cas has that covered," Dean replied, gesturing to him. "He doesn't need sleep or rest, so I'm sure he'll find something in no time."

Cas leveled a, 'I'm-an-angel-of-the-Lord-not-your-secretary' look at Dean, which the older Winchester shrugged off.

"Cas is running on borrowed juice," Sam countered, earning a glower from the angel. "We should be helping, considering this is _our_ problem."

"No, it's not 'our' problem, Sam," Dean said caustically. "It's my problem. I'm the one who took on the Mark, damn the consequences; I gotta live with it."

"Or die with it?" Sam snapped back. "Because if anything happens to you and you've still got the Mark, you know what happens!"

"Of course I know!" Dean's face was turning a mottled red, yet beneath all the anger and frustration, there was a glistening desperation in his eyes, and when he spoke again, his voice wavered with brokenness. "I am just trying to do the right thing, man, 'cause I'm so sick and tired of doing the wrong one."

Sam bit back his next retort. He understood, he really did. After he'd screwed up with the demon blood and setting Lucifer free, he'd wanted to make it right, wanted to save as many lives as possible to make up for his mistakes. But he also knew that 'trying to do the right thing' while he was still hopped up on demon blood was a slippery slope. It started out with good intentions, but before he knew it, Sam had gone down a road he'd never imagined, or wanted.

"Look, man, I get it," he said sympathetically. "I do. But the Mark…it doesn't distinguish between killing monsters and killing innocents."

"I'll figure out a way to control it," Dean quickly rejoined. "Cain did, right? He lived for centuries without turning into a homicidal maniac."

Sam sighed. "Yeah." It wasn't that he doubted the Mark could be controlled, it was just…Dean wasn't exactly the poster boy for discipline. Though he certainly made up for it in stubbornness.

Cas had been pretty quiet throughout the argument, so Sam turned to ask his opinion, when the microwave four feet away whirred to life. A split second later the door burst off the hinges with a crack and shower of sparks, sending glass and metal shrapnel spiraling through the air. Sam threw his arms up instinctively to shield his face, a few pieces pelting his shoulder and torso, but thankfully not piercing clothes or skin. He lowered his arms cautiously. The microwave spat out a few more electrical splinters before falling silent, leaving a plume of smoke wafting up from the scorched interior.

Sam just stared for a long moment before shooting a startled look at Cas, who had both hands braced on the edge of the kitchen table as he blinked dazedly at the microwave. Speaking of control issues…

Dean's expression was just as slack-jawed, but it quickly morphed into an irate glare directed at the angel. "Dude, what the hell?"

"I'm…sorry." Cas's brow furrowed with such intense chagrin that Sam thought he might pop a blood vessel. Or several.

"What the hell was that?" he sputtered, adrenaline making his face hot and palms sweaty. His gaze quickly swept around the kitchen, ticking off other items that could potentially explode. The toaster and coffeemaker suddenly seemed like grenades ready to blow up in their faces, and Sam inched away from them toward the center of the room.

Cas shook his head as though clearing brain fog. "I don't know. I'll…I'll just go for some fresh air again." He turned to leave, but Dean sidestepped into his personal space, forcing him back.

"No way, you're gonna tell us what's going on. Why is your mojo on the fritz?"

Cas scowled at him. "I don't _know_."

Sam's heart rate began kicking up again. "If your grace is starting to burn out, then we need to find a way to replenish it, right?" Looked like Cas's situation was now the more urgent one, and Sam was _not_ feeling a twinge of resentment at that. It wasn't like Cas had asked for this to happen. Besides, they really did need his help with the Mark, so if that meant saving his life first, then that's what they needed to do.

"It's not burning out," Castiel said. "When it does, I'll be more lethargic and infirm."

"How do you know that?" Dean asked.

Cas looked away toward the wall as though some fascinating bug was perched there, which set off warning bells in Sam's head.

"Cas?" Dean pressed in a low tone that clearly said, 'don't-give-me-any-bullshit.'

The angel let out an exasperated sigh. "It had already started while you were… 'missing.'"

Sam frowned. He remembered Cas being off his game—that was when Sam's elbow had been injured in the botched attempt to capture a demon for questioning. Sam had kind of blamed Cas for it, even though it hadn't actually been the angel's fault; Sam had just been pissed about losing another lead on his brother. But he'd stopped calling Cas for help after that…except the one other time, when Cas had sounded like he was hacking up a lung and Sam had told him to forget it, that the lead had minor potential. Only, it had actually led to Dean.

"How bad did it get?" Sam asked in a soft voice, afraid of the answer, ashamed that he hadn't asked before.

Cas rolled his shoulder in discomfort. "It doesn't matter."

"'Course it does," Dean retorted. "We need to know what's coming."

A muscle in Castiel's jaw ticked. "I was tired and run down. I couldn't heal myself. Most likely when the time comes again, I'll simply slip into a coma before the grace fizzles out." His lips twitched humorlessly. "A more peaceful death than I've ever had before. Or deserve."

The knots in Sam's stomach were twisting into kinks of their own. 'When the time comes _again_.' Cas had been dying, like literally approaching death's doorstep, and Sam hadn't noticed. Hadn't _bothered_ to notice, because oh, there had been clues, and he was damn well smart enough to have figured them out. For instance, the fact that Cas knew he wouldn't be able to heal himself meant he'd been injured somehow and his healing powers hadn't worked. And he hadn't called Sam for help. But then, why would he have? Sam had been singularly focused on Dean.

Dean's shoulders were rigid, but he kept his voice level when he spoke. "You started sleeping, didn't you?"

Cas nodded. "Yes. Even when I wasn't trying to. There was an incident while I was driving. But as you can see, I'm fine at the moment."

Dean snorted. "Except for things exploding."

Cas frowned, gaze turning inward for a moment. "Yes. I'll…try to stop doing that."

"Okay, wait," Sam put in, attempting to shake himself from self-flagellation and focus on what he was hearing. "So you'd gotten that bad before, and how'd you fix it? Did you take another angel's grace?"

Cas's eyes darkened, and Sam winced at the simmering disgust he felt wafting from the angel. "I didn't," Cas said stiffly. "Crowley did."

Sam's brows shot up. " _Crowley_?" After everything that conniving bastard had done, Cas went to _him_ for help?

 _Well why not,_ a small voice whispered, _you weren't available_.

"I didn't ask for or want his help," Cas retorted sharply. "I was on my way here after you'd called to say you found Dean. Hannah was with me, and we were attacked by a rogue angel at a gas station." He looked away. "I wasn't strong enough to fight, and she'd left me for dead, went back to torture Hannah, I think. Crowley showed up and killed her, but not before cutting out her grace, which he then gave to me. I tried to refuse, but like I said, I wasn't in much shape to put up a fight." Cas shrugged. "In the end it was for the best, as I made it here just in time." He didn't elaborate on what he was in time for, but Dean ducked his gaze in shame and Sam swallowed hard against the lump forming in his throat.

His mind was reeling as well. Cas had nearly died at some random gas station. He'd been dying for days, weeks, without saying a word, had been hanging by a thread it sounded like, and had still given everything to come to Sam and Dean's aid. And if he hadn't made it, if Crowley hadn't intervened…then Dean probably would have killed Sam. By the greenish tinge to Dean's complexion, the same thoughts were running through his mind.

"Why would Crowley help you like that?" Sam asked hoarsely.

Cas gave him a wry look. "He didn't want Dean staying a demon any more than we did."

Sam couldn't believe he was actually feeling gratitude toward the dickwad. After all, the Mark had been Crowley's fault to begin with.

"But as I said," Cas continued. "My grace isn't currently fading like that, so if you'll excuse me, I should get back to the archives before it does." He swept out of the kitchen, pausing on the steps of the threshold. "Sorry about the microwave," he said over his shoulder, and then disappeared down the corridor.

Dean paced half the length of the table and rapped his knuckles on the wood, a haunted look in his eyes.. "I take it back; I'm not ready for a case."

Sam didn't say anything, but glanced at the charred remains of the microwave, his insides feeling just as singed by guilt and worry. Ignoring a problem had never gotten them anywhere good, and Sam had once again made the same mistake, this time with Cas. And only by the grace of the King of Hell was the angel still with them. For now.

Sam's eyes drifted to his brother's arm and the red, raised indent poking out from under his rolled up sleeve. He was surrounded by impossible problems, forced to prioritize the lives of the two people who meant everything to him. Dean's soul was gradually being corrupted by the Mark, and Cas was slowly dying.

Sam had thought curing Dean from being a demon would give them a measure of control back, a place to regroup and tackle the situation anew. But all that happened was to reset the clock. Control was an illusion.


	3. Chapter 3: Take These Broken Wings

**A/N: Oh my gosh, 29-pieces-of-me made _fan art_ for this story! I'm so honored! I wish I could include a link but the site isn't letting me. You can check it out on Deviant Art though, under her same screen name of 29-pieces-of-me.**

* * *

 **Chapter 3: Take These Broken Wings**

Castiel sat with his elbows braced on the study table, one hand rubbing his temple against the pulsing headache that'd been developing since yesterday. After the incident with the microwave, he'd been trying to tamp down on his grace, keep it coiled tight so it wouldn't flare up and short circuit things. It had worked, too. No more lights flickered or buzzed when he passed by, and he'd been able to convince Sam and Dean that he was fine, that it was over.

Except, the energy that had been escaping in random bursts like solar flares was now building up pressure as Castiel fought to keep it in. His head was pounding, and every time he moved, white speckles flitted across his vision. It was making it difficult to maintain concentration on the text he was reading. Actually, he couldn't even remember what the words had described before they'd blurred together like diluted ink. Castiel sighed. This was not helping matters.

Worse than the headache though, was the tingling that had started at the base of his shoulder blades and had gradually worked its way up until he began to feel cramps where his wings used to be. Which made no sense to him at all. He didn't have wings anymore; therefore they shouldn't _hurt_. But they did. Small twinges at first, that then escalated into near-crippling spasms. Phantom pains, he believed they were called. Amputees sometimes got them: sensory pain in the lost limb despite the fact it was no longer there. He would have found it a fascinating academic topic if he weren't the one currently experiencing it.

" _Cas_."

He jerked upright, elbows crinkling the delicate parchment of the Babylonian tome in front of him. For a brief moment, his vision whited out, and when it cleared, Castiel found Dean standing right next to him in what he was certain was a violation of personal space.

"What?" he said, attempting a casual tone. The strain that leaked out anyway he would chalk up to annoyance, and he roughly smoothed the page he'd creased.

"We called your name three times."

Castiel looked up again, and noticed Sam was sitting to his left at the table with some open books, mouth pressed into a tight line of concern. When had they joined him?

Castiel rolled his shoulder, which was a mistake, for it only sent a rippling spasm out behind him. He winced. "Sorry, I was thinking."

Dean's eyes narrowed. "Thinking usually hurt this much?"

"You've claimed it does in the past."

"So you're Mr. Comedian now." Dean crossed his arms. "Cut the crap and tell us what's going on with you. First the light show, then the microwave, and now you're clearly in pain."

"It's fine," Castiel ground out. Translation: it's really not, but there's nothing we can do about it so can we please drop it? At least, that's what the Winchesters were supposed to do. They never were good at following the script though.

"It's not fine. Look at yourself!"

"Cas," Sam spoke up, always with a gentler tone than Dean. He leaned forward on the table earnestly. "Come on, man, talk to us. We can't help if we don't know what's wrong."

Castiel sighed. In the past, he could have simply flown away to avoid this conversation. Though, with the amount of pain his 'wings' were in, that likely wouldn't have been an option.

"You can't help anyway because I don't know what's wrong," he answered begrudgingly. "I was trying to keep my grace from interfering with electromagnetic devices, and…and now my wings hurt. Only they _shouldn't_ , because I don't have them anymore." He shifted his shoulders again, just to test them, and once more it brought about a pained grimace. "It's a very strange and disconcerting sensation."

Both brothers' brows rose in surprise, and they exchanged one of their, 'what the hell are we supposed to do about _that_?' looks. Castiel wanted to say he told them so, but he squinted against a flare in his headache instead.

Dean finally stepped back from crowding Castiel. "This has to be about the stolen grace, right? Did Crowley poison what he gave you or something?"

Castiel quirked a dubious brow. "I doubt he could have done anything like that."

Dean reached into his pocket and pulled out his cell phone.

Sam let out a disbelieving snort. "Seriously? You're just gonna call him up and ask?"

Dean shrugged. "Why not? We were best buds just last week, until he sold me out to you, of course. But since he technically helped save me, I won't hold it against him."

"And if he did poison Cas?" Sam asked.

Technically, the demon had saved him as well, but Castiel didn't feel like pointing that out again. He just wanted all of this to _stop_.

"Then I'm going to track him down and put a devil's-trap bullet between his eyes." Dean scrolled through his contacts, pausing to flick an acerbic look at Sam and Castiel. "And that's not the Mark talking, by the way." He punched dial, followed by the speaker button, and set the phone on the table. The line rang three times before clicking.

"Squirrel," Crowley's annoyingly chipper accent broadcasted. "I hear you're back to your old charming self."

"And I hear a lot of it is thanks to you."

"Send me an edible arrangement. And if you're calling to apologize, you can shove it up your arse."

Dean blinked. "Why would _I_ apologize?"

Sam cleared his throat obtrusively, shooting a pointed look at Dean.

He glowered in return, but changed his tone to something slightly more amiable. "Look Crowley, I heard what you did for Cas."

"Ah, so this is gratitude for saving your pet angel? How saccharine."

Castiel gritted his teeth; it really rankled him to owe anything to a demon, despite the unusual history the two of them had. Or maybe it was because of that history; the lines between good and evil when it came to them both had become quite muddied.

Dean put his palms on the table and leaned over the phone, as though his menace could be translated through the cellular waves. "What'd you do to that grace, Crowley? Poison it? Cast some sort of spell so it would kill Cas?"

For a moment, the King of Hell didn't respond. "I take it dear Castiel is not doing so well," he said slowly. "And you're trying to blame me."

"He was fine until you gave him that second grace."

Well, not fine, but not like this, Castiel mentally amended. Sam gave Dean a wry look that said the same, to which the older Winchester just shrugged.

Crowley made a sound of disgruntlement. "Apparently you going Deanmon fried a few brain cells. Why would I go to the trouble of procuring some grace, poison it, and then give it to him when he _was already dying_!"

Castiel arched a brow at the Winchesters. Fair point. Besides, he still didn't think such a thing was possible.

"Because you wanted him to help make me human again," Dean barreled on. "Once that was done, he'd be dying again."

"He'd be dying bloody hell anyway! You think stolen grace lasts forever? All I have to do is sit back and wait. And believe me, I have time. Not that I particularly want Castiel dead, just so you know. I currently don't have a beef with him."

"You did before," Dean pointed out.

"Yes, well, times change." There was a strange ring of bitterness in the demon's tone that confused Castiel, almost like disappointment and regret.

"Look," Crowley scowled. "Ask Castiel's girlfriend. She was there and watched the entire thing. I didn't do anything to that grace." The line disconnected as Crowley hung up.

"I told you it wasn't him," Castiel said.

Dean pocketed his phone angrily. "Well, I'm still not fully convinced. Where's this Hannah chick? Maybe she can back up his story or contradict it."

Castiel looked away. "She's busy. We don't need to call her."

"Maybe she'll know what's going on," Sam suggested.

"She won't. There's no precedent for an angel stealing another angel's grace." Because it was an unthinkable crime. That Metatron had committed the heinous act first, that Castiel had done it second in self-defense, did not change the nature of his sin. Or that he deserved whatever consequences came afterward.

Sam leaned back in his chair, forehead creasing ruminatively. "Maybe this is happening because you have more than one grace inside you. I mean, I know the first one was burning out, but it wasn't completely gone. And then you add a second one into the mix, and you've got like, one and a half graces inside you, so maybe it's too much."

Castiel frowned in thought. "An angel's grace flows through our true form, including our wings. I suppose…if it's true that I have…more, the extra energy is trying to find somewhere to go, but can't. So it's…resonating." Painfully. Castiel reached up to rub his temple again, this time from fatigue. He was glad he'd been able to help Sam cure Dean, he really was. But part of him wished the whole thing could just have been over. He mentally chastised himself for such a thought; he was still a long way from earning redemption for his mistakes.

"So what do we do?" Sam asked.

"Nothing," Castiel replied with a sigh. "The grace will slowly start to burn out, and then it won't be a problem."

"Except you'd be dying again," Dean said pointedly.

Castiel didn't respond, but turned his gaze back to the ancient text in front of him. He had to find a way to save Dean before that happened. That was his path to absolution. He jumped when Dean leaned over and slammed the book closed.

"You want to die? Is that it?"

"Dean, what…?" Sam sputtered.

"That's sure as hell what it sounded like. Crowley had to _force_ that second grace down your throat, and now you're just sitting here impatiently waiting for it to burn out again?"

Castiel's jaw tightened. "I will not murder more angels simply to prolong my own life."

"That angel tried to kill you first."

"That doesn't make it right, Dean!" Castiel shoved himself away from the table, putting a few more inches between him and the seething Winchester. Pain lanced down his spine from hitting the back of the chair, and he staggered to his feet to relieve the pressure. "I accept my fate," he said bitterly. "It's no more than I deserve for my sins."

Dean's jaw worked as though he wanted to spew more caustic words, so Castiel simply glared at him head on, daring him to contradict anything Cas had said. When Dean didn't respond, Castiel's shoulders sagged.

"Just let me get back to work on the Mark." Except, he couldn't seem to locate the table through the gray haze that suddenly coated his vision. He blinked a few times to clear it, but was ineffective.

Dean snorted. "You can't even see straight."

"Maybe if you stopped yelling," Castiel retorted, even though it wasn't Dean's fault. It was his own, but he was certainly not going to unleash the roiling grace and risk exploding something else that could hurt the Winchesters. They'd been lucky with the microwave.

"Cas," Sam spoke up gently. "Maybe you should just get some rest for the night, or at least until some of the extra grace fizzles out. The books will still be here tomorrow."

"So will I," Dean said gruffly, though with a minor note of concern and remorse.

Castiel wanted to argue, but the pain had become too great, and he knew he wouldn't be able to focus. He thought about laying down in the backseat of his car outside, since it was rather spacious, but even without real wings, his aching back and shoulders would feel too cramped.

He swallowed his pride and asked roughly, "May I borrow one of the bedrooms for a short time?"

Dean's anger instantly vanished into something more contrite. "Of course, Cas. You never have to ask for that."

Castiel gave a small nod of gratitude, and followed Dean out of the library, feeling Sam's troubled gaze on his back. Dean led him down the hallway and opened the door next to his own room and across from Sam's. Like all of the living quarters in the bunker, it held a simple yet plush memory foam mattress, and a small writing desk to the right. A mounted shelf extended across the length of the back wall above the bed, devoid of any items.

Castiel stepped inside. "Thank you."

Dean glanced over the bare walls, throat bobbing uncomfortably. "This is the room I should've given you when…after the angels fell."

Castiel dropped his gaze to the floor. His time as a human, particularly in the beginning, was not something he liked to think about.

Dean cleared his throat. "This whole mess is partly my fault, isn't it?"

"You didn't know what the Mark would do," Castiel automatically tried to console him. Funny how old habits died hard. "Though I do wish you had given it more thought before diving in."

Dean snorted humorlessly. "Not that. I mean, the Mark's all on me, I ain't denying it. I meant…if I hadn't kicked you out of the bunker, you wouldn't have been forced to steal another angel's grace."

Castiel's shoulders slumped with the weight of everything that had happened in the past few years. It had been non-stop. The Apocalypse, the civil war in Heaven, Leviathan, Purgatory, Naomi, the fallen angels. Castiel's mistakes had brought them here, not Dean's.

"It's not your fault, Dean. Even if I had stayed here, become a hunter—albeit a crappy one," he added with attempted levity. It failed. "The other angels would have caught up to me eventually, tortured me because of my role in casting them out."

"Sam and I would've come for you," Dean said forcefully, desperately, as though begging for something, either understanding or forgiveness. But Dean never had to ask for those. "You wouldn't have had to steal another angel's grace to escape."

Castiel sighed. "I would have anyway. I needed to be an angel to help defeat Metatron, to help you with the Mark. It was my choice." He sank onto the edge of the mattress, stiffening as his shoulder blades seized and a soft gasp escaped his lips.

Dean eyed him for a long moment. "Would an entire bottle of aspirin do any good?"

"Probably not, but thanks anyway."

"Alright. Just…take it easy. We still need you around." Dean put his hand on the door knob, pausing to give Castiel a meaningful look. "I'm gonna help you find a way to fix your grace."

Castiel just nodded, and Dean closed the door. Then he lay down on his side, tucking one arm under his head. _Don't make promises you can't keep_.


	4. Chapter 4: Chain Reaction

**A/N: Thanks so much to everyone who's reviewed so far! And all those bad feelings you had...you were right. ;)**

* * *

 **Chapter 4: Chain Reaction**

Dean's eyes snapped open at the first strident buzz that issued from his alarm clock. He bolted upright just as the LED dashes displaying the time flashed like a neon casino sign, and the desk and floor lamps started flickering.

"That's it," he growled, and scrambled out of bed. Grace burning out, his ass. More like this crap was gaining intensity, especially if Cas was supposedly 'holding it in.' So either it'd gotten to be too much, or the angel had given up trying. Neither of which boded well.

Dean charged out of his room, nearly colliding with Sam who had also come bursting into the hall. They exchanged keyed up looks before turning as one toward Cas's door. Sam gripped the knob and shouldered it open, both of them spilling in only to come to an abrupt halt on the threshold. Cas was on his knees at the foot of the bed, one shoulder braced against the side of the mattress. His other hand clutched his forehead, which was turned slightly away. Even so, there was an odd glow suffusing between his fingers that sent Dean's heart into his throat.

"Cas!" His instincts urged him to rush to his friend's side, but he froze when Cas looked up, dropping his hand to the floor to brace himself. Bluish-white light pulsed around the rims of Castiel's eyes, and a few sparks sizzled from the corners, spritzing like slivers of lightning that dissolved before hitting the rug to catch fire.

Sam sucked in a sharp breath. "Oh my god." Neither he or Dean moved, unsure what to do, afraid to get too close.

"Cas?" Dean called again, voice rising an octave.

Castiel moaned and squeezed his eyes shut. It only made his eyelids flush red. "This…shouldn't be happening."

" _What's_ happening?" Sam asked, taking a hesitant step forward, but the lights droning again and more silver splinters shooting from the angel stopped him short.

"It's too strong," Cas ground out around a clenched jaw. A shudder rocked his shoulders, and he curled in on himself with a choked grunt.

Dean closed the five feet between them, ignoring the warning in his gut, and dropped down next to Cas. The hairs on the back of his neck stood on end, and he felt static in the air as though he were crouching next to a live wire.

"Stay back, Sam." The Mark would protect Dean, at least. He gripped Castiel's shoulders as another spasm ripped through the angel. Shit, Cas was practically _vibrating_. Tingles zinged up Dean's arms, and the Mark started to burn, but he shoved the pain down and held Cas tighter.

"Breathe through it," he urged. "I got you, just breathe through it." Dammit, what the hell did he know? What if whatever this was didn't pass? He craned his neck over his shoulder to meet Sam's equally worried gaze.

A strangled sound escaped Cas's throat, and then he suddenly went limp. Dean's fingers frantically curled in the trench coat to hold him up. "Shit, Cas?" The prickling sensations on his arms had petered out, and he felt the air in the room settle as whatever fritzing energy Cas had been giving off dissipated. Sam darted forward then to kneel on Cas's other side, and helped Dean shift the angel so he was leaning back against the bed. The light that'd been radiating from behind his eyes had also vanished. Cas lolled his head back and blinked at them.

"You good now?" Dean asked, though Cas really didn't look it. His breathing was too ragged and a sheen of sweat had broken out across his forehead.

Cas didn't speak for a long moment, brows tightly knitted together. "No," he finally said hoarsely. "The grace, it's _not_ burning out. It's…burning _up_."

Sam frowned. "What do you mean?"

Cas tried to sit up straighter, but slumped with a pained grimace, and Dean belatedly remembered his wings. Or, not-wings, whatever. He slipped an arm under Castiel's lower back and eased him forward an inch so most of his weight was supported by Dean's shoulder.

"It's…building up energy," Cas wheezed. "More than normal, and I…can't control the…surges."

"Has that ever happened to an angel before?"

Cas shook his head. "Not that I know of."

"Okay," Dean put in. "Can't believe I'm gonna say this, but we need to call another angel. How do we contact Hannah?"

"Pray?" Sam suggested.

"Well, she's not going to answer me, considering last time we met she was demanding my execution."

Sam's mouth pressed into a thin line. "She probably won't answer mine either. Any other angel we can call?"

"I'll reach out to Hannah," Cas spoke up, pushing away from Dean to brace his own weight. "The gateway to Heaven is open now."

Dean planted a firm hand on his shoulder. "Don't you even think about taking off."

"I'll be fine, Dean," he insisted. "It's only bad during the eruptions."

"And if another eruption happens while you're driving? Nuh-uh, we don't need you having another 'incident' behind the wheel, so you're staying put."

"You two don't need to concern yourselves with this."

"Like hell we don't. You're part of this family, Cas, so your problems are our problems."

Cas angled such a wry look at Dean that he felt as though he'd been punched in the gut. Yeah, how often had he said that in the past?

 _"You're like a brother to me."_ But he didn't give a shit about the war in Heaven, and kept asking Cas for help on other things. No, demanding it. _"Of course, because your problems always come first."_

 _"I told you something was off with him since he got back from Purgatory."_ Yet Dean never followed up. And then a brainwashed Cas had beaten him to a pulp in Lucifer's crypt before taking off with the angel tablet. _"So you can take your little apology and you cram it up your ass."_

 _"I do now see how difficult life can be and how well you two have led it. And I think you'll be great teachers."_ Then the clincher: _"You can't stay here."_

Dean swallowed the whopping lump of guilt lodged in his throat, and squeezed Cas's arm. "I mean it this time." Had he not meant it all the times before though?

Sam rolled his shoulder awkwardly. "Let's get you back on the bed, and then I'll go pray to Hannah." He looked to Dean, and on a silent count of three, they hauled Cas up and helped him sit on the mattress. At least Cas was managing to stay upright on his own now.

As Sam left, Dean placed the back of his hand on Cas's forehead. "You're running a fever."

"A minor one," he replied, sounding hollow and distant.

Dean's stomach clenched some more. "Stay put, alright? I'll be right back."

He went to the kitchen and grabbed a couple ice packs from the freezer. When he returned to the room, Cas was in the same position, though listing a fraction to the side. Dean sat next to him on the bed and held one ice pack to the back of his neck, the other between his shoulder blades. Cas stiffened and let out a sharp exhale, but didn't flinch away. After a few moments, he began to relax.

"That help with the wings?"

Cas nodded slowly. "Yes. Thank you."

They fell silent for several minutes, and then Cas began to fidget. "I'm sorry," he said.

"For what?"

Cas sighed. "Lots of things."

Dean's throat constricted. He did not want to go down that road again, especially since he owed the angel way more apologies than Cas did him. "It's okay, man. Really."

"I'm distracting you and Sam when you need to be focusing on the Mark."

"No biggie, I'm fine right now."

Cas snorted. "You keep using that word. I do not think it means what you think it means."

Dean blinked dumbly at him. "Dude, did you just quote pop culture to me?"

A shy smile tugged at Cas's lips. "I guess. Did I even do it right?"

Dean grinned. "Well, referencing _The Princess Bride_ makes you more of a nerd like Sam, but yeah, you did it right. And I'm more fine than you, by the way."

"You know what 'fine' stands for, don't you? Freaked out, insecure, neurotic, and emotional," Castiel deadpanned.

"Have you even watched either of those movies?"

"No, Metatron just downloaded all the information into my brain while I was his captive."

Dean shook his head. "Oh, that is sacrilege. When your grace is fixed and I've got this thing off my arm, we're doing a classic movie marathon. All the other big evils in the world can take a vacation."

Cas angled a small smile at him, but Dean noticed that it didn't reach his eyes. Because there was no telling if either of them would ever make it to that point.

* * *

Sam paced the length of the war room for the twentieth time. He had no idea if his prayer had even reached Hannah. It had kinda felt like leaving a voice mail, but was he supposed to have given his phone number so she could call him back? How long would it take her to get here, if she even decided to come?

He ran his hands over his hair and glanced down the tunnel toward the living quarters. It'd been a few hours since he'd woken up to blitzing lights and grace crackling from Cas's eyes, and there'd been no further incidents or 'power surges'. But he wasn't naive enough to believe that would be the end of it—or callous enough to shove the problem under the table this time. He just had no idea what to _do_.

When a knock sounded through the front door, Sam spun around and sprinted up the steps to the balcony. He yanked the heavy metal slab open and nearly sagged in relief at the sight of the brunette angel standing outside.

Hannah's expression was tight, and her gaze kept flicking around guardedly. "You said Castiel was in trouble?"

Sam attempted to swallow his discomfort at having her here. After all, she had wanted Cas to kill Dean, but now they needed her. He stepped back and held out an inviting arm. "Something's wrong with his grace."

Hannah cocked her head in bird-like confusion. "He just replenished it; it shouldn't be fading so fast."

"It's not." Sam gestured impatiently for her to head down the stairs.

Casting him a wary look, she nevertheless entered the bunker and preceded him down to the war room, eyes sweeping every direction as she took in the structure.

"It started with Cas accidentally blowing up light bulbs," Sam explained. "Then a microwave. He tried to, I dunno, keep a tighter restraint on the grace, but it caused phantom pains where his wings used to be."

Hannah turned to him now, brow deeply furrowed. "That does not sound good."

Sam blinked at her, and then shook his head. Right, angels, masters of understatement. "Yeah, well, it's not. And early this morning grace started spitting from his eyes like electricity." He strode through the library urgently, barely checking his pace so Hannah could keep up. He wanted to snap at her to hurry, but then, when had he ever seen an angel run?

They reached Cas's room, and Hannah followed him inside, pulling up short when she spotted Dean. He was sitting on the bed, pressing ice packs to Cas's back while the angel lay curled on his side, muscles taut with tension. Dean and Hannah immediately exchanged hostile glares, but Sam was thankful when his brother refrained from any scathing remarks.

Hannah's gaze drifted to Cas, and she skirted the edge of the bed to come around and face him. He tilted his head back to look up at her, giving Sam a glimpse of the creases of pain around his eyes and mouth.

"Hello, Hannah," he said, voice gravelly.

"Castiel," she replied with a nod, frowning at his state. "What happened?"

"Crowley says he didn't do anything to the grace he gave Cas," Dean spoke up gruffly. "You were there though, so is he telling the truth?"

Hannah frowned at Dean before addressing Cas again. "The demon that gave you the second grace? No, he didn't do anything to it."

Cas nodded. "I didn't think so."

"You're sure?" Dean pressed.

Hannah's shoulders heaved in exasperation as she finally met his gaze and responded, "I'm sure. After he cut it out of the rogue angel, he went straight to Castiel and gave it to him."

"Do you have any idea what's wrong with him?" Sam interjected, trying to counter Dean's abrasiveness.

Hannah pursed her lips thoughtfully, and then placed a hand over Castiel's brow. She closed her eyes, canting her head in obvious concentration. Sam tried not to fidget as he waited for her conclusion.

Hannah suddenly jerked away and stumbled back a step, her hand tucked close to her chest as though she'd been stung. Wide eyes whipped to Sam and then Dean, causing Sam's heart rate to kick up a notch.

"What is it?" he demanded.

Cas struggled to push himself up onto one elbow. "Hannah?"

Her gaze dropped to meet his. "The two graces…together they've triggered some kind of chain reaction."

Dean slid off the bed and stormed around the foot of it. "What kind of chain reaction?"

She gave herself a small shake, still stunned, and then lifted her head with staunch grimness. "The kind that could potentially level the state of Kansas when it reaches critical mass."

Sam's jaw went slack, and he threw an alarmed look at Dean. His brother had gone two shades whiter at the news, and now everyone turned their eyes toward Cas, whose mouth had completely disappeared in a thin line.

"Any chance it'll reverse itself?" Sam managed to ask. "Start fading like it did before?"

"With how it's progressing…" Hannah glanced down at Castiel. "No."

Cas tried to sit up the rest of the way, swinging his legs over the edge of the bed. "I can't be here then."

"You're not going anywhere." Dean roughly nudged his way past Hannah and grabbed Cas's shoulder to push him back down. "We'll figure this out."

Sam turned to the other angel. "How long do we have?"

She frowned. "I'm not sure. A few days, perhaps. Not more."

"There's gotta be something we can do," he insisted.

"We cut it out," Dean said abruptly.

Sam's brows shot up as he gaped at his brother, while Castiel flinched away from Dean with a horrified expression.

Dean crossed his arms and scowled at them both. "Don't look at me like that. We get rid of the grace, problem solved. I know being human wasn't easy, but it's better than blowing up the state, don't you think?"

Cas inched back to lean against the headboard. "Extracting the grace won't make it inert."

"No," Hannah agreed. "In fact, Castiel's control is currently the only thing keeping the grace from exploding this very minute."

Sam felt like the rug just got ripped out from under him. "But Cas can't hold it in forever."

"Which is why I need to leave."

"And I told you we're not giving up without trying," Dean snapped, then whirled on Hannah. "So come on, think! How do we defuse the grace?"

Hannah's face scrunched up. "We need another vessel to contain it."

Sam sputtered. "You want to shove it into someone else?"

She quirked a bemused look at him. "Not a human vessel. A container. It would have to be of Heavenly origin in order to hold the grace long enough to remove it a safe distance from the earth."

Sam just shook his head. They needed to fling it into deep space?

"Okay, so you got one of those lying around?" Dean asked.

Hannah's lips pursed. "No."

Dean threw his arms up and started to pace around to the other side of the bed. "Well, that's just great. Have anything _useful_ to add?"

Hannah flicked an uncertain glance at Castiel.

Cas apparently caught the look, and shot back a warning one of his own. "Hannah, no."

"No what?" Dean said, craning his head back and forth between them.

Hannah lifted her chin defiantly. "Metatron had lots of assets stored up, in Heaven and on earth."

Sam didn't know whether to curse or laugh hysterically. "Metatron? Seriously?"

"He would know where such an item could be found. And where Castiel's leftover grace is."

"Wait," Dean spoke up, finally losing the harsh edge to his tone. "Cas can get his grace back? Which means he wouldn't be dying anymore?"

Hannah nodded.

"I will not endanger humanity by bargaining with him for myself," Cas glowered at them.

"Sounds like humanity is in danger anyway," Dean pointed out, then looked to Sam in silent question. Both of them were apprehensive about going to Metatron for help. After all, the son-of-a-bitch had _killed_ Dean, thereby turning him into a demon. But they also knew they had no other choice.

"Alright, so can you bring Metatron here?" Dean asked Hannah.

"Metatron _cannot_ be trusted," Cas growled, and glared at the female angel, which she returned unashamedly.

"We don't have to trust him," Dean said. "We just have to get him to talk."

A hard lump started gathering in Sam's throat, but this time it wasn't related to the douche-angel, and he found himself studiously evaluating Dean's posture and mood. On the surface, Dean seemed fine: determined, hard-ass exterior covering up the worry he truly felt. But Sam was afraid about what might have been brimming just underneath.

Dean arched an expectant brow at Hannah, and she gave Castiel an apologetic look before nodding to the Winchesters. "I'll return as soon as I can."

With that, Sam turned to escort her out of the bunker, leaving Dean and Cas throwing black glowers at each other. They _needed_ to do this. But Sam couldn't help the niggling beginnings of worry coiling around his gut.


	5. Chapter 5: Ticking Time Bomb

**A/N: Some lines taken directly from the episode "The Hunter Games"; they're not mine.**

* * *

 **Chapter 5: Ticking Time Bomb**

Sam watched Dean sitting by Commodore 64, jiggling his leg with the intensity of a motorized massage chair. It was starting to get on Sam's nerves. "Would you cut that out?"

Dean jerked his head up, which at least served to interrupt the bouncing. He scowled at Sam. "Forgive me if I'm a little amped up at bringing the guy who _killed_ me into our home."

Sam's jaw tightened. "I'm not happy about this either, Dean, but what other choice do we have?"

Shaking his head, Dean got up to pace. "I know, I'm not saying we don't do this. It just sucks."

"Big time," Sam agreed, and then pursed his lips in thought. "What if Metatron can also give us answers about the Mark?"

Dean paused to throw him an incredulous look, and then slowly glanced down at his arm. Almost subconsciously at this point, his other hand drifted over to cover the red scar. Dean swallowed hard. "Let's just deal with Cas's grace first, then see what we can do about that."

Sam let it drop, and they resumed waiting for Hannah in silence. Half an hour later, Sam's phone beeped with a text message. "They're here," he said, pulse starting to ratchet up. The last time they had seen Metatron, the angel had driven a blade through Dean's chest, thereby turning him into a demon.

Dean's muscles looked just as tense. "I'm gonna check on Cas. Meet you in the dungeon."

Sam watched him go, then turned to head up the steps and open the door. Hannah stood outside, a short figure in handcuffs with a hood over his face next to her. The restraints made Sam feel marginally better. He gave Hannah a clipped nod, and stepped aside so she and Metatron could enter. Without saying a word, they escorted the prisoner down to the dungeon where Hannah gently pushed him into the chair in the center of the Devil's trap. Sam didn't miss how she looked around as though searching for Dean.

"He must be returned—intact," she said, tone laced with heavy meaning, before she left the dungeon.

Taking a deep breath, Sam approached their captive and yanked the hood off the bushy head. Metatron blinked repeatedly as his eyes adjusted to the light, and he cast a curious gaze around the walls and floor.

"Lovely room. It's where you bring the kinky chicks. Am I right?"

Sam drew his shoulders back. "I'll ask the questions here. You—your only job is to provide information."

"Oh, well. Information does happen to be a specialty. Got about two billion fun facts up here." He lifted his cuffed hands to tap the side of his head. "Of course, whether I choose to cough one up or not is another matter." He gave Sam a toothy grin.

"Oh, you will," a voice came from behind the sliding stacks, and Dean walked in.

Sam felt a flicker of satisfaction when Metatron's eyes went wide. "Didn't see that coming, did you?"

Metatron made a few sputtering sounds of disbelief. "Are you kidding me? What does it take for one of you idiots to stay dead around here!"

"You should know," Dean said, and rolled up his sleeve to reveal the Mark.

Metatron fidgeted in his chair. "Ah, you became a demon. Who knew the Mark was so toxic? Well…actually, I did." He chuckled, but then his brows bunched together as he studied Dean.

"Yeah, not a demon anymore." Dean shrugged nonchalantly, and only Sam caught the slight note of strain in his brother's voice.

"So let me guess, you want a way to get the Mark off." Metatron sat up a little straighter, that smarmy mien quirking his mouth again and filling Sam with the urge to wipe the floor with his face.

"Do you know how to do that?" he couldn't help but ask, ignoring the peeved expression Dean rolled his way. All anyone else would see, though, was the 'bad-cop' persona waiting to be unleashed.

Metatron lolled his head back casually. "May-be."

"That's great," Dean jumped in. "But let's start with something simpler. Where's Cas's grace?"

"Ahhh." A wide smile revealed yellowing teeth. "Ass-tiel isn't doing so well, is he? That stolen grace about to burn out, snuff him out like a candle flame?"

Sam's hands curled into fists at how much pleasure Metatron seemed to be reveling in at the notion. "Actually, the opposite."

Dean stalked around the back of the chained angel. "Yeah, apparently mix two borrowed graces, shake and stir, and you get the makings of an atomic bomb."

Metatron craned his neck to follow Dean's movements, expression once again blank with confusion. But then it cracked, and Metatron barked out a laugh. "You mean he's gone nuclear? That's fantastic!"

Dean lashed out, grabbing Metatron by the collar and yanking him back against the chair. "We hear you had a nice cache of Heavenly treasures while you were playing God. So you're gonna tell us where to find Cas's grace, along with a nice box to put the unstable stuff in before it blows a crater in the entire Mid-west."

Metatron rolled his eyes. "Little Hannah has been imitating a birdie, I see."

Dean gave him another rough shake, cracking Metatron's neck hard enough to give him whiplash. Then he strode around to the front to loom menacingly over the angel's puny vessel.

Metatron held up his cuffed hands defensively. "What, just like that, social hour's over?"

"Yes. And now we're moving on to our keynote speaker. Which is you…" Dean reached into his jacket and pulled out an angel blade. "With us asking the questions and me taking the personal pleasure of carving the answers out of you."

A muscle in Sam's jaw ticked, but he tried to resist letting his apprehension show. It wouldn't do for Metatron to call their bluff. He tried to catch Dean's eye to silently confirm it was just a bluff…but either Dean was too focused or was purposefully ignoring him.

The douche-angel finally lost his cheeky demeanor. "Just—whoa, whoa, whoa. Hold on there, badass. Lighten up. Why do you just assume I'm not gonna be helpful?"

Dean leaned over him, holding the tip of the blade to Metatron's neck. "Because you're a dickwad."

"But I'm _your_ dickwad. I have a special place in my…non-heart for you both. And Castiel, to which end—ta-da!—I would be tickled to help you solve these little problems."

Dean straightened. "Alright, let's hear it."

Metatron rolled his neck. "I do have something you can put the borrowed grace in. A nice little relic that will hold the primordial fusion at least temporarily so it won't automatically go kablooey when released." His lips curled upward. "Ever hear of the Ark?"

"The biblical boat?"

Metatron's jaw dropped. "No, you moron. The Ark of the Covenant!"

Sam exchanged a flabbergasted look with his brother. "The Ark?" he stammered.

"Okay, not _the_ Ark. A miniature replica. God made me a paperweight version for being employee of the millennium. But since it was made by _Him_ , it's tough stuff."

Dean rolled his eyes.

"So where is it?" Sam asked.

Metatron pursed his lips and scrunched his shoulders up. "Ah, not so fast. That first little tip I gave you—a freebie, just 'cause you're you. Everything else? Is gonna cost you. Big."

For a moment, Dean didn't say anything, and when he glanced at Sam, there was a hardened, almost eager glint in his eyes. "You're confused," he said, turning back to Metatron. "See, I'm gonna get some information. About this box, about the Mark…and I'm gonna enjoy every minute of it because you're gonna tell me everything—all of it—and it ain't gonna cost me a damn dime."

Sam shifted his weight nervously; things were poised to spiral wildly out of control, and he didn't know what to do about it. They needed answers; Sam _wanted_ answers, but that gleam in Dean's expression made his blood run cold.

"Mhm," Metatron hummed. "I don't think so. You _really_ need a special container that only comes from Heaven, not to mention Castiel's original grace because I'm sure he'll be too damaged from this whole ordeal to survive, even if he becomes human again. And you need this Mark taken off you. And in order to do that, you really need me. So I repeat my offer: each tip costs you."

Dean twirled the angel blade and leaned in close enough he could probably smell Metatron's breath. "I'm gonna ask this exactly once before it gets ugly. Where's Cas's grace and this 'paperweight'?"

Metatron scoffed, and before Sam could react, Dean had flipped the angel blade around and rammed the pommel against Metatron's face.

"Dean!" Sam cast a wary look over his shoulder, afraid Hannah would walk in any second. This was not what they'd agreed to.

"Where's Cas's grace?"

Metatron grunted. "Good, Dean. Go darker."

Dean hit him again, splitting open the angel's cheek and splattering blood through the air.

"Go deeper!"

Another thwack of metal against flesh punctuated the air, and Sam surged forward. He tried to grab Dean's arm, but he just kept hitting. Sam finally wrenched him off and shoved him back several steps.

Metatron cracked a bloody, manic grin. "That's it. Keep going. Surely you've noticed every time you respond, when the Mark gets you all twitchy, you fall deeper under its spell. You think roughing up a few monsters and demons makes it worse? Try messing with the scribe of God, Bucko!"

"Dean, stop!" Sam gripped his brother's arm with both hands, near the shoulder and at his wrist, forcing the angel blade to stay angled down. "What the hell are you doing?"

"We need him to talk, Sam!"

"Not like this! Dean, _you_ can't go there!"

"And we don't have time for his games!"

Sam kept his body between Dean and Metatron behind him, trying to push Dean backward toward the exit. This was not how it was supposed to go. Sam had walked in wanting nothing more than to beat the crap out of Metatron, but seeing that look in his brother's eyes, that hunger for violence and bloodlust he thought had been cured with the demonism…Sam just wanted to get Dean away from here. But how was he gonna get Metatron to tell them about the Mark now? Or where Cas's grace was?

A scuffling sound came from behind him, and before Sam could turn around, a heavy weight barreled into his back, knocking him into Dean and sending both of them crashing to the floor. Sam scrambled to get on his feet again as Dean grunted and tried to buck him off. Silver glinted in his peripheral vision, and the next second, white-hot pain like a poker speared between his lower left ribs.

* * *

Castiel lay face up on the bed with several ice packs wedged between him and the mattress. He'd finally become numb enough that pressure on his back didn't hurt as much, and Dean had just been in to swap out the cold compresses with new ones. They hadn't said much to each other since the brothers had decided to bring Metatron here for questioning. Castiel thought it was a tremendously bad idea, but his vote apparently didn't count. They needed to contain the unstable grace, and the Winchesters were convinced Metatron was their only answer. Castiel knew of another option, however, a last resort, though he also knew better than to share it with Sam and Dean.

He stared helplessly at the ceiling. It was one thing to just 'go gentle into that good night,' when Castiel could have hidden his dying from the Winchesters and Hannah had agreed to respect his wishes in that regard. But now his stolen grace was going haywire and threatening lives. So once again, Castiel was going to be responsible for multiple deaths if they didn't do something soon. He sighed; he never could seem to do anything right, even when he was trying.

The light clack of a shoe crossing the threshold alerted him to a visitor, and he knew by its softness that it wasn't one of the Winchesters. Castiel lifted his head a fraction to find Hannah watching him, mouth pinched in a concerned moue. It was…nice to have a member of his family actually caring about his well-being. He'd gotten used to being on the outs with all the other angels and them wanting him dead, no matter how much he'd only wanted to help his family.

She rolled her shoulder in discomfort. "How are you doing?"

Castiel almost said 'fine,' but remembered how Hannah had taken it the last time he'd used that answer, and then he recalled his conversation with Dean. That memory brought a wan smile to his lips. "The pain is less," he said instead, knowing Hannah would understand that better.

She came forward, and Castiel pushed himself upright, swinging his legs over the side of the bed so he could face her properly.

"I take it Metatron is here."

"I know you disapprove, Castiel, but he is the only one who can help you."

He looked away in frustration, hating the situation, hating himself for having brought everyone to it. "Hannah, I must ask a favor of you."

She straightened. "Anything."

Castiel took a deep breath. "If an alternate containment source can't be found in time, and I have to…defuse the situation, I need you to pick up where I left off in helping Dean."

Hannah blinked at him incredulously. "Castiel, he bears the Mark of Cain."

"Dean is a good man who's made some bad decisions."

"Even after everything, after he became a demon, you're still loyal to him," she said with obvious censure.

"I know you don't understand," Castiel softened his tone. "But Sam and Dean…they're like family to me."

Hannah's brows furrowed in genuine confusion. "What about Heaven?"

"I can have more than one family."

Her gaze turned inward, as though she were intently trying to parse that out. Castiel couldn't make her understand though, couldn't explain how important Sam and Dean were to him. It was just…the way it was.

He bowed forward, bracing his elbows on his thighs, and rubbed both sides of his temple. He was supposed to be resting, but he couldn't just sit by when this whole fiasco was his mess to begin with. Not that Castiel thought he could get any answers out of Metatron. After all, when there had been a mole in his angel army, he'd called Sam and Dean for their interrogation skills. Though, that hadn't exactly gone well…

Muffled shouts followed by an echo of a crash had Castiel whipping his head up. _Oh no_. Exchanging an alarmed look with Hannah, they both bolted for the door and toward the dungeon. The pounding in Castiel's head had suddenly taken a backseat to the erratic racing of his heart. Why hadn't he insisted on being there? He knew Metatron couldn't be trusted! Or…had something happened with Dean? It was too soon, too soon after curing him to let Dean face the angel that had killed him.

Castiel careened around the archive shelves and into the dungeon. His heart leaped into his throat at what he saw. Metatron was curled up on the floor against the back wall, moaning senselessly. Even from across the room, Castiel could see blood streaming down Metatron's face. But he spared only a brief thought for the angel, for his gaze snapped to Dean kneeling next to a prone Sam, hands fisted in Sam's shirt as he pressed furiously against the younger Winchester's torso. Sam's face was screwed up in pain, and he let out a stifled groan as Dean pushed down harder. On the floor by Sam's hip was an angel blade coated in crimson fluid.

Hannah swept in behind Castiel. "What happened?" she demanded, marching toward Metatron and crouching down beside him.

"He attacked us," Dean growled viciously. "And stabbed Sam."

A garbled chuckle issued from Metatron then, and he turned a bloody and bruised face toward them. "Thought I'd go for notching two Winchester deaths on my belt!"

Dean's nostrils flared, and if he wasn't currently pressing as hard as he could to keep his brother's life blood from pouring out across the floor, he probably would have resumed the beat-down where he'd left off.

Castiel didn't want to think about how Metatron could have possibly gotten the drop on the two experienced hunters, and so he knelt down on Sam's other side. A red stain had already pooled out from beneath Dean's fingers, soaking a patch of flannel three inches in diameter. Sam lifted his head, only to gasp and drop it back down.

"Sam!" Dean's voice cracked.

"Dean, move." Castiel tore Dean's hands away from Sam's side so he could have full access to it, and without even thinking about the potential consequences, poured angelic healing into the sucking chest wound. Golden light suffused from his palm to halo Sam's torso, but then it flared as searing agony suddenly engulfed Castiel. A shockwave ripped out from inside him, as though he was imploding into a billion pieces. Someone screamed, and everything went black.

* * *

 **A/N: Uh oh... 0:-) Reviews are love!**


	6. Chapter 6: Raise the Stakes

**A/N: Some lines in the later scene are from the episode "Inside Man."**

* * *

 **Chapter 6: Raise the Stakes**

A guttural moan rumbled in Dean's throat, and his eyelids fluttered blearily, filling his vision with an opaque red haze. What the hell had just happened? He shifted his shoulders, grunting when pain lanced down his spine. The corner of the sliding shelf unit was poking him in the kidney, so he rolled away from it to brace himself on his hands and knees. Wispy tendrils curled along the edges of his sight and he blinked repeatedly to clear them. What was with the red glow? Wait, the bunker's emergency lights were on. Why…?

There was a mechanical whir somewhere within the walls, and the red bulbs extinguished as the main power came back on. Dean's gaze immediately sharpened on Sam lying flat on the floor next to him.

"No." Dean surged forward and gripped Sam by the collar, his other hand frantically shooting toward the gaping stab wound. Only, there wasn't any blood. There wasn't even a hole in Sam's shirt. Dean yanked the flannel up, revealing nothing but skin, whole and intact. He rocked back on his haunches. Sam was alive; Metatron hadn't killed him.

Sam groaned and pried his eyes open. "D'n? Wha-the-'ell happened?" he slurred, and tried to sit up.

"I don't know." He finally looked around the rest of the room. Hannah was slumped upright against the back wall, head turning side to side as she regained her senses. Metatron was on the floor next to her, making a low keening sound, and the prisoner chair had been flung into the far corner. And in the center of the room, amidst a scorched Devil's trap, lay Cas. Dean's heart plummeted into his stomach. Oh god, were those wing prints?

"Son-of-a-bitch." He scrambled toward the angel, scuffing through charred paint. The streaks weren't feathers though, just shadowed ripples burnt into the concrete. "Cas?" Dean gave him a small shake, but got no response. Sam crawled over and held his hand over Castiel's mouth and nose.

"He's breathing. Sort of."

Dean glanced around helplessly, gaze locking with Hannah's as she stumbled to her feet. "What the hell was that?"

She shook her head dazedly.

"Cas?" Sam called, and Dean looked down to find Castiel's face scrunching up as he clawed his way back to consciousness. Hannah inched forward hesitantly.

"Cas?" Dean echoed, squeezing the angel's shoulder.

Cas slowly opened his eyes to reveal pupils blown wide and cloudy. "Wh-what happened?" he asked groggily.

"You tell us," Dean groused. "You alright?"

Cas blinked at him.

 _Right, stupid question_.

"Was it because you healed me?" Sam asked as he and Dean helped haul Cas into a sitting position and hold him steady when he reached up to clutch his forehead. "Which, you know, thanks."

A frown tugged at Castiel's mouth. "I…suppose when I used the grace…there was a surge."

"Understatement," Dean muttered, glancing around at the singed floor and busted chair. It was probably a miracle they hadn't just blown the whole bunker to oblivion.

Metatron coughed then, and pushed himself upright to sag against the wall. "Wow. I gotta say, not even I was expecting that." He made a slurping sound and leaned sideways to spit a glob of blood and saliva on the floor. A gargled chuckle rattled in his throat. "Too bad all that power will kill you. Otherwise you could have been the new God, Castiel—successfully this time."

Cas's face darkened, even though he wasn't currently facing the douche-angel in order to glare daggers at him. Dean almost volunteered to smack the dickhead for him, but the rush of excitement that flooded his system at the prospect was simultaneously like an ice bucket over his head. Dean knew he'd crossed the line earlier. He wasn't even sure when the transition had happened, when he'd gone from purposeful interrogator to reveling in the feel of Metatron's soft flesh giving under his blows. Part of him—a dark, festering blight deep within his soul—blamed Metatron for hurting Sam, wanted to punish the angel more for almost killing his brother. But another part of Dean knew that if he hadn't lost his cool, Metatron wouldn't have been able to catch them off guard. That was on him.

He needed to get away from the dungeon for a little bit. It'd probably even be best if Sam took over the questioning from this point forward. Dean was just lucky Hannah had come in after Metatron's escape attempt, so the angel's injuries could be explained as self-defense. They'd be screwed if she decided to pull the plug because he'd used what she considered 'excessive force.'

 _Who are you kidding?_ Dean glanced back at Metatron's swollen cheekbone and split lip. _Any normal person would call that excessive_.

"Can you stand?" he asked Cas, hoarse voice betraying his simmering emotions. Cas and Hannah were probably too stunned by the mini explosion to pay attention, but Dean knew by the tense set of Sam's jaw that he wasn't fooled. After all, he'd been there and witnessed Dean going off the rails.

Cas nodded, and proceeded to get up off the floor, with the brothers' help. The lights buzzed at a low frequency, causing Dean and Sam to freeze. Hannah merely angled a curious look at the fixtures, while Cas squeezed his eyes shut until the droning stopped.

"Sorry," he rasped.

"Okay, let's sit you down somewhere that's not here." Though, really it was Dean who needed to be elsewhere.

"What about me?" Metatron whined, struggling to stand without the use of his arms for balance. "I'm the victim here!"

Dean's hand subconsciously fisted in Cas's trench coat, but before he could lose it again, Hannah whirled back around and marched toward Metatron. She pressed two fingers to his forehead roughly, and an instant later his cuts and bruises had vanished. All evidence of Dean's crimes erased.

"Now sit down and shut up," she ordered.

Sam arched a surprised brow as Hannah then stormed out of the dungeon. Dean let his brother take most of Castiel's weight as they followed, and he paused in the outer corridor to cast one last look inside before engaging the lock. Metatron's lips curved in a sneer as the sliding shelves skidded shut.

The four of them shuffled out to the library, the second most spacious area besides the garage where Dean could pace through his growing agitation. Sam eased Cas into one of the chairs, patting his shoulder reassuringly.

"What happened in there?" Hannah demanded.

"You saw." Dean gestured at Cas. "Cas had some kind of power surge."

"Not that. With Metatron. How did he get the angel blade away from you?"

Sam flicked a quick look at Dean before dropping his gaze to the floor. Cas probably would've been eyeing him with angelic laser beams if he weren't currently pinching the bridge of his nose against what was likely a killer headache.

Dean lifted his chin as though he had nothin' to hide. He was damn good at faking it, too. "Sam and I were having a little pow-wow on how best to get answers, and Metatron decided to make his move, I guess. It was a stupid move, too." He turned away from their faces though, not wanting to see the pointed glares or 'I-told-you-so' expressions. Because Metatron's 'stupid move' had almost cost Sam his life. And healing Sam could have cost Cas his, not to mention the state of Kansas. Yeah, Dean really needed to get a grip on the Mark.

Sam cleared his throat. "Okay look, we may have had a…hiccup."

Dean canted his head wryly, earning an eye roll in return.

"But we're all okay," Sam continued. "And before Metatron tried to escape, he admitted he does have a Heavenly artifact that can contain the unstable grace. Said it was a replica of the Ark of the Covenant, or whatever."

Hannah's brows knitted together. "Alright. Where is it?"

"Uh, we didn't get that far." Sam once again cast a furtive look Dean's way, which Dean really wished he would stop doing. He'd simply lost his temper for crying out loud; he wasn't the one going radioactive!

Sam lowered his gaze to Cas. "He, uh, also said that removing the stolen grace could kill you unless we have your original grace."

Cas didn't say anything. He didn't look surprised, or panicked, or worried, just thoughtful. "Metatron said my current power level could rival God's…"

Dean felt something inside of him snap. "So what? You planning on going Godstiel on us again?" The look of scorn Cas shot him in return made Dean instantly feel guilty. He knew Cas better than that.

"What that means," Castiel ground out. "Is I may be able to remove the Mark myself."

Sam sucked in a sharp breath, while Dean could only stare dumbly in response. Get rid of the Mark, just like that? He didn't know whether it was desperate desire, or if the Mark somehow sensed that it was true, but Dean's forearm started to tingle.

"Well let's try it," Sam exclaimed.

"Castiel," Hannah interjected urgently. "Using the grace will only accelerate the chain reaction, as you just saw when you healed Sam Winchester."

Dean's hopes snuffed out like a candle in the face of a hurricane. Of course, because when could they ever catch a break?

"But after we get the special container, Cas can remove the Mark, and then we drain the grace before it blows," Sam barreled on, his frenzied expression causing a fissure to rend through Dean's heart; he hated causing his little brother pain.

Hannah pulled her shoulders back in frustration. "More likely you'll detonate the grace before you can safely get it out of Castiel. At the very least he'll be too damaged for even his own grace to save him!"

Sam's cheeks flared as he fought to hold in a return outburst. He wanted to cure Dean so badly, but Dean wasn't willing to sacrifice Cas to do it.

A heavy sigh from Castiel interrupted the mounting tension. "None of this matters because Metatron will not give up the items."

Sam exchanged a defeated look with Dean, who felt a whole fresh wave of guilt at his failure.

He rolled his shoulder, attempting to focus on the problem at hand. "We need to change the game. Change the stakes."

Hannah quirked a brow. "What do you mean?"

Dean fell silent for a long moment as he tried to sort past his tumultuous emotions and come up with a plan. He felt everyone's eyes on him, but it was Cas he looked to first. They needed to succeed for him. His life was on the line, and all because of the maniac angel sitting in their dungeon. Metatron had started all of this when he took Cas's grace, and the fact that they needed him to fix it rankled Dean to no end.

He straightened as an idea began to form, and this time the eagerness that stirred him to life had nothing to do with the Mark's thirst for blood. No, this was pure, unadulterated justice.

"I know what to do."

0-o-0-o-0

The four of them marched back to the dungeon in full accord with their plan. It had taken less convincing than Dean would have thought to get Hannah on board. Despite the disagreements the two of them may have had in the past, at least she genuinely cared about Cas. That was one thing Dean and the angel chick could unite on.

The storage brackets slid open, revealing Metatron sitting on the floor, legs stretched straight out. "Lost your autonomous privileges, I see." He leaned forward. "Good. You all better keep him on a tight leash."

Dean just smiled genially. "No worries, I'm not into fulfilling your bondage fetish. Maybe after we're done here, she will." He cocked his head toward Hannah, who unfortunately couldn't even follow the conversation, and had probably never heard of a dominatrix before.

Metatron pushed himself off the floor to stand, though without the Angel Tablet to juice him up, he was really just a small, pathetic dweeb.

"So, you gonna help us?" Dean asked.

"Mhm, are you gonna pay the piper? And by the way, the cost has doubled."

"You don't get to make demands, Metatron," Cas growled. "You're not in charge here."

The smarmy bastard gave them a simpering smile. "Oh, I'm afraid I am. I know about the Mark. I have your grace. I make the rules. It's called leverage, boys. Learn it, live it, love it."

Castiel looked at Dean, who nodded encouragingly. They had decided Cas should have the honor of doing this, and Dean was gonna savor it.

Cas strode forward, angel blade in hand, and before Metatron could even process what was happening, Cas had sliced the blade across his neck. With his other hand, he held a little glass jar beneath Metatron's chin as bluish-white grace spilled into it. Then he stepped back, and Hannah moved in with a swipe of her hand to heal the slit throat. It all happened in a few seconds, way shorter than the son-of-a-bitch deserved.

Just as Metatron gasped in a startled breath, Sam pulled out a gun and shot him in the leg. Dean was a little jealous he couldn't have participated, but he knew it would have been a bad idea. They needed to make progress here, not five steps back from him losing it. He certainly was enjoying the experience vicariously though.

Metatron yelped and jerked back against the wall. "Ow, ow!" One hand clutched his thigh as the other tried to hold himself up.

"We have your grace, Metatron," Cas said, sounding stronger and more self-assured than he had in days. "You're mortal now. So you will answer our questions, or Sam will, um…what's the phrase? Blow your fricking brains out. It's called leverage, Metatron."

Sam smirked. "Learn it, live it, love it. Now, where's this special box and Cas's grace?"

Metatron's face puffed red as he seethed at them.

Cas cocked his head. "Nothing to say? Fine. Sam, shoot him." He turned a dismissive shoulder on Metatron, who instantly started whimpering like a whipped puppy.

"Alright, alright!" He scowled. "I'll take you to them."

Dean had to work at keeping a smug grin off his face.

Sam moved closer to him, turning his back on Metatron and speaking in a low tone. "Listen, you and Cas should stay here since you're both kinda, um, unstable."

Dean's initial reaction was to yell that there was no friggin' way he was letting Sam go off alone with Metatron, but the concern mixed with anxiety in his brother's face made him reconsider. For one thing, Sam was probably right about Cas. Getting the Heavenly paperweight and his grace to him sooner would be better, but they couldn't very well go off and risk blowing an entire city's power grid. And he shouldn't stay at the bunker by himself. After Sam nearly died, Dean wanted nothing more than to insist he stay with Cas while Dean took Metatron on a road trip. But that was an even more catastrophic idea.

Dean sighed, running a hand over his hair. "Yeah, alright." At least Sam wouldn't actually be alone; Hannah would be going as well. Dean just didn't have much confidence in her as Sam's back-up.

Sam nodded to Hannah, who grabbed Metatron's shoulder and began shoving him toward the exit.

Cas held out the bottle of grace to Dean. "You should hold onto this. I probably shouldn't be anywhere near extra grace right now," he said ruefully.

"Hey, be careful with that!" Metatron carped. "I'll remind you that the Ark isn't going to keep the grace contained forever. Who else are you gonna get to fly it out to Pluto?"

Dean pocketed the small jar. "Actually, that's the one part in all this I do have covered."

Sam gave him a questioning look, but he didn't elaborate.

"Wait!" Metatron blubbered as Hannah propelled him into the hall.

Sam gave Dean and Cas one last look of silent wishes for them to hang tight and stay safe. Dean nodded for Sam to do the same. Then Sam left, and his retreating footsteps gradually petered out.

Dean feigned a shudder. "I'm gonna have to bleach the back of the Impala to get Metatron cooties off it when they get back."

Cas didn't respond, but slumped one shoulder against the wall. He'd either been faking the strength he'd displayed in front of Metatron, or he'd expended what little reserve he had left.

Dean suppressed a sigh, and reached out to take Cas by the elbow. "Okay, back to bed for you."

Cas didn't protest as Dean led him back to his room. He sat on the bed, but didn't lay down on the ice packs, which had long since turned lukewarm and slushy.

"Nice poker face back there," Dean complimented, patting Cas on the back. "Though you may have jumped to threatening to blow his brains out a little fast."

Cas looked away toward the wall, which to Dean screamed classic avoidance mode.

"What the hell—you weren't bluffing." He shook his head. "Come on, Cas, we couldn't actually kill Metatron."

"He's our best option, not our only one," Cas replied.

Dean frowned. "What other option is there? 'Cause I didn't hear you speaking up before."

Cas's shoulders heaved with a sigh, and he finally turned back to meet Dean's gaze. "If Sam and Hannah don't make it back on time, or if Metatron was lying, there's possibly a way to minimize the extent of the explosion. A focusing sigil, something to prevent the grace from wiping out the state. Perhaps only a few acres instead."

Dean blinked at him for a long moment, processing what Cas wasn't saying. "Taking you with it." He surged to his feet. "Dammit, Cas."

"If it becomes necessary, yes. The grace will detonate anyway, Dean. I hope Sam and Hannah find this artifact and make it back in time, but if they don't, I will not be responsible for more deaths if I can help it."

Dean whirled on him. "First of all, stop thinking like that. Sam _will_ find this box and your grace, and we'll save the world by the skin of our teeth like we always do."

"I know," Cas said simply. "I have faith in that. But, Dean, you have to be prepared for the possibility that saving the world does not necessarily include saving me."

"Not an option."

Cas's lips twitched, and he resumed gazing at the wall. Dean's eyes traced the bare shelves. They needed something, something to declare this as 'Cas's' rather than just a guest room. Dean didn't really know what an angel might decorate his living space with; they didn't seem to have anything in the way of personal possessions. Aside from angel blades, of course. Dean would have to pick up some stuff. Maybe a _Constantine_ poster. Cas should understand the reference now, at least.

Yeah, Dean would spiff this place up, in case Cas needed it after the grace transfusion. Or just because he wanted Cas to know this was his home too. And always would be.


	7. Chapter 7: Life and Death

**A/N: Some lines and events lifted from the episode "Book of the Damned," but obviously with this AU twist. And there's only one more chapter after this. Yet another story coming to a close. *sadface***

* * *

 **Chapter 7: Life and Death**

Sam had been on many uncomfortable car rides in his time, considering half of his life had been spent on the road, but this one was topping the charts into downright miserable and _infuriating_. And it'd only been an hour. Hannah was in the backseat with Metatron, and the newly-ex-angel was as squirmy as a two-year-old. He'd been regaling them practically nonstop on how everything _felt_ so different as a human.

"I had no idea these sensations could be so powerful. Hey, can we stop for ice cream? You know, it never tasted all that great as an angel, but now…"

Hannah made a disgusted noise and turned her head away to look out the window.

"Party pooper. Hey, Samtastic," Metatron leaned forward to rest his cuffed hands on the back of the driver's seat. "What do you say? Pit stop for hot fudge sundaes?"

Sam craned a peeved look over his shoulder. "No. Cas could go critical at any moment, and don't forget you're still in the blast radius, so sit back and shut up unless you have directions to give."

Metatron heaved a dramatic sigh and slumped back in the seat. It was a _really_ good thing Dean hadn't come along, or the douche ex-angel would have been thrown out of the vehicle at ninety-miles-an-hour. Sam was just beginning to get used to the silence when a peppy tune started humming from behind him.

"How do we get rid of the Mark?" he asked abruptly, wondering if Metatron's newfound touchy-feelyness would make him more charitable. Sam wanted to believe Cas could do it without causing irreparable harm to himself, but if that wasn't the case…no, Sam couldn't ask Cas to sacrifice himself like that. So they were back to Metatron.

"Truthfully?"

Sam snorted. "If you can even be that." He caught sight of Metatron in the rearview mirror rolling his eyes.

"I don't know. It's old magic…God-level magic. Or Lucifer level, but you can't ask him, exactly, can you?"

Sam gritted his teeth. "What about the tablets?"

"No, there's nothing in them about the Mark."

"So when you said you could help us, that was—"

Metatron shrugged one shoulder guilelessly. "I was just trying to buy time till I could screw you over."

Sam's fingers whitened around the steering wheel. It was a good thing the dick was currently out of arm's reach, unless Sam wanted to crash the car.

"He's telling the truth," Hannah put in unhelpfully.

"Yeah," Sam muttered, and turned his focus back on the road.

Twenty minutes later, Metatron finally directed Sam to pull up in front of an old Victorian style building. Even though it was late afternoon, no lights were on from what Sam could see, and the parking lot was empty.

"What is this place?" he asked as they got out of the car.

Metatron sighed wistfully. "An under-appreciated treasure trove."

They marched up the platform steps, and Sam took a moment to pick the lock. When it clicked, he pulled the door open for Hannah to drag Metatron in first, and then he followed. The three of them stopped in a grand foyer lined with shiny hardwood floors and Greek-style support pillars.

"Oh, come on," Sam muttered. "You expect us to believe that you hid Cas's grace in a library?"

"Nobody goes to libraries anymore. It's the safest place in the world."

Rolling his eyes, Sam flicked on the lights, illuminating rows and rows of bookshelves packed with volumes.

Hannah stepped away from Metatron, her head tilted in that weird bird-like manner that socially awkward angels did. "I can feel Castiel's grace. It's here, but you've hidden it somehow."

Okay, guess that was progress. At least Metatron hadn't been lying to them about that. "Where is it?" Sam asked.

Metatron bunched up his shoulders. "Honestly, I have no idea."

Sam whirled on him, pushing him into a chair and clamping a hand around the poorly bandaged gunshot wound in the ex-angel's leg. Metatron yelped and writhed to get away, but Sam squeezed harder. "Where is it?" In his peripheral vision, he saw Hannah start to move forward as though to intervene, but she ended up holding herself back.

"Oh! Gah! I don't know, I swear! I had another angel hide it, even from me." He threw his head back and howled again, spittle flying from his mouth. "You know, in case someone tries to torture the information out of me! Case in point!"

Sam straightened, releasing his grip. Righteous fury was boiling inside him, but he had to work at keeping himself in check. He couldn't blame an outburst on the Mark, after all. "Where is the grace?" he asked in a low, measured tone.

Metatron shifted in the chair. "I told the angel to hide some clues in some of my favorite books." He held up his handcuffed wrists. "Mother, may I?"

Sam inhaled sharply and glanced at Hannah. Her expression was carefully neutral, which was also getting on his nerves. How were they supposed to work together if he couldn't read her? But she was an angel and Metatron was a measly human now, so he wasn't much of a threat. Sam reached into his pocket for the key and undid the cuffs.

Rubbing his hands together gleefully, Metatron limped over to a shelf and pulled out a book. Sam snatched it out of his hands and flipped it open. There was a note stuck between the pages.

"'What is the maddest thing a man can do?'" he read, and then glowered at the ex-angel. "It's a riddle? What's the answer?"

"Um, the—the answer to the riddle will lead to another book. And inside that book, you'll find Castiel's grace." Metatron grinned. "We're gonna work this out together, okay? Teamwork."

Sam snorted, and slapped the book against Metatron's chest before striding away to search the shelves.

"You know," the douchebag called after him. "We really can make a good team. Kind of like a buddy comedy, without the comedy."

"Or the buddies," Sam shot back. "You killed my brother, remember?"

"Eh, good point." Metatron turned to peruse the book spines in front of him.

Sam forced himself to take a calming breath. All they had to do was find Cas's grace and this special box, and then they could get rid of Metatron—one way or the other.

He turned down one of the aisles and paused at a decorative pedestal nestled in a small nook between shelf units. On top was an old Bible open to Exodus, and next to it was a golden box, five-by-three inches, with two bronze poles looped through metal rings on the sides. On the lid knelt two sculpted angels facing each other, wings folded over their shoulders and extended forward so their tips almost touched.

Sam stared at it for a long moment. Paperweight, huh? He picked it up gingerly, wary of being struck down by lightning, even though technically this wasn't the _real_ Ark of the Covenant. "Hey, Hannah?"

He carried the box back out to the open area of the library and held it up for Hannah to inspect. She didn't touch it, but her brows knitted together with intense concentration.

"Yes, I can sense its power. This is the vessel we need for the unstable grace."

Great, one down, one to go.

Hannah jerked, a choked cough gasping from her throat.

"Hannah?" Sam exclaimed, reaching out to catch her elbow as she dropped to the floor, face contorting in pain. "What's wrong?"

Her mouth moved around desperate gulps for air, but only strangled sounds came out.

"Poor Hannah," Metatron crooned then, stepping out from the next row. "Swam so far just to drown in shallow waters. Isn't it ironic? Don't ya think?"

Sam's eyes widened at Metatron's blood-tipped fingers. "What did you do?"

"What I told you I would—screw you over." He lifted his hand and slammed it against the side panel of the shelving unit. Sam couldn't see what sigil he might have painted in his blood, but there was a sharp crack, and the section of aluminum shelves next to Sam and Hannah started to tip over.

* * *

Dean was hovering like a mother hen, as Castiel had heard Sam call it before. He'd never experienced it himself, only witnessed such anxious care directed toward Sam, and Castiel wasn't quite sure what to do with it. With the ice packs all used up, Dean had resorted to soaking a washcloth in cold water and draping it across the back of Castiel's neck. It was a nice gesture, but Castiel didn't tell him that the compresses weren't working anymore. He could feel the flush in his skin that had turned to tingles similar to when he'd been stung by a bunch of bees while gathering honey. It hadn't bothered him then, but now it was quite uncomfortable. And it was getting worse.

Castiel couldn't tell how much longer he could hold the churning grace in. He could feel it ripping him apart on the molecular level, and his natural angelic healing was having a harder and harder time keeping up with repairing the damage. He glanced at the clock. How much more time should he give Sam before taking matters into his own hands?

The alarm clock suddenly whined and 'brrped', sending sparks out from the display as the LED dashes went dark. Castiel gritted his teeth in annoyance. To think at one point he hadn't cared how many electromagnetic devices he blew up when he walked into a room.

Dean arched a brow at the fried clock from where he was sitting next to the bed. "That's one way to hit the snooze button."

Castiel felt a flare of indignation at Dean's apparent nonchalance, though he knew it was just one of the hunter's coping mechanisms. Castiel needed to find a way to manage his roiling thoughts and emotions as well. Which usually involved one particular outlet…

"Perhaps I should try to remove the Mark now," he suggested.

Dean's brow furrowed. "What? Why? We don't have the box yet and you could set yourself off."

Castiel rolled a shoulder awkwardly. "Or I can control the surge. I don't think we should wait, Dean. I may not be in a position to try by the time Sam and Hannah get back."

Hazel eyes narrowed on him like storm clouds over a turquoise sea. Dean didn't respond for a long moment, and Castiel could see the war raging within the Winchester. He wanted a cure, desperately needed it, and yet guilt and fear held him back. How could Castiel reassure him that this was the right thing to do?

Dean leaned forward, interlocking his fingers across his knees. "Was Hannah right? Will removing the Mark hurt you to the point where even your grace won't heal you?"

Castiel glanced at the floor, unsure how to phrase his answer. It was always easier to lie when things were wrapped in half-truths, such as it was _possible_ , but not certain. But he didn't get a chance to say that before Dean let out a derisive snort.

"That's what I thought. Then no. Not now, not ever, Cas. Not at that cost."

He sighed. "Dean…"

"You said you deserved to die for your sins. Well then what about me? I don't deserve to be saved, Cas, not after everything I did."

"That wasn't you, Dean, it was the Mark. It's different."

"The hell it is." Dean scooted to the edge of his chair, lashing out to grip Castiel's forearm like a vice. "All you ever tried to do was the right thing. I see that, Cas. Okay? Crowley, Purgatory, hell, even trusting Metatron—I know you meant well."

"My intentions mean nothing," he ground out. Dean had more or less told him that once, after he'd run off with the Angel Tablet.

"I tortured souls in Hell, killed dozens in Purgatory and _enjoyed_ it. Lied to Sam and let an angel possess him, which led to Kevin's death. I wasn't there for you when you needed help. I tried to paint all those decisions as doing the right thing, but at the root of them all? I was selfish. So tell me _why_ do you deserve death more than me?"

Castiel's chest constricted at the heartbroken plea. How could he explain? How could he make Dean understand? Humans were his father's creation, souls that could choose to be good or bad, and in either case deserved mercy and forgiveness. Protecting them was Castiel's mission.

The grace pulsed inside him, continuously building in intensity. His shoulder blades buzzed and twinged from the blockage where wings used to be. He didn't have long, and refused to let this chance go to waste.

Castiel clasped Dean's arm in return, resolution giving him strength. "That's not it, Dean. It's that you deserve _life_."

Dean's eyes wavered with the frayed ends of hope and despair. He'd been fighting the good fight for so long, against impossible odds, and that vulnerable, lost young man that Castiel saw underneath all the emotional walls and facades tugged at the angel's heart. As it always had.

"You've always been worth it," Castiel added, and then without warning ripped Dean's sleeve up, exposing the Mark. Before Dean could even protest, Castiel clamped his hand over the scar and felt his grace erupt with the force of a supernova. Golden light burst throughout the room, swallowing everything in its blaze. Castiel's hand felt as though it were on fire, and he screamed as the Mark bubbled and sizzled beneath his palm. A shockwave shook the foundation of the bunker, and with one final burst, Castiel collapsed sideways on the bed, gasping for breath.

It took several moments for the residual aura of energy to diffuse and for the lights to come back on. When they did, Castiel spotted Dean lying on the floor. He slid off the bed to crumple next to the Winchester and check for a pulse. Dean was alive. Not only that, but the Mark was gone from his arm.

Castiel only had a brief moment of sheer relief before crippling pain ripped through his chest. He doubled over with a strangled cry. The grace was approaching critical mass now; he had to get out of there. He blindly struggled to his feet, for his vision was coated in a glowing halo and he felt the zings of sparks spritzing from the corners of his eyes. When he glanced down, it seemed his chest was glowing as well.

Castiel stumbled into the hallway and toward the exit. He needed to get a safe distance from the bunker. Even with the sigil he had planned, he'd likely obliterate a good chunk of the woods outside. Castiel hoped the resulting public attention wouldn't cause too much trouble for the Winchesters, or expose the secret Men of Letters hideout.

He barely made it up the stairs, sparks of grace flying from his eyes to singe the railing and floor. He barreled into the door and out into fresh air, daylight burning his already stinging eyes. Dropping his angel blade from his sleeve into a shaky hand, Castiel staggered toward the trees with a silent apology sent out behind him on the wings of a prayer.

* * *

Sam dove out of the way as part of the bookcase came crashing down where he'd been a moment before. He managed to keep a hold of the miniature Ark, and flipped onto his back as books went flying across the floor around him. He stared in shock at Hannah's now-still body lying half under the metal shelf unit. No, she was an angel; she'd be fine. Except for whatever hoodoo Metatron had cast on her…

Sam snapped his gaze toward the gap where the bookcase had fallen, and spotted the son-of-a-bitch in the next aisle, reaching for a volume from an undisturbed shelf.

"All right," Metatron hummed to himself. "First things first—find what I really came here for." He lifted a note from between the pages and held it up to the light. "'What two things do you need to succeed in life?'" His shoulders jumped in a little happy dance. "Ignorance and confidence."

Sam's eyes widened, and he frantically rifled through his pockets for the note from the first book. They were quotes… He pulled his cell phone out next and began googling the phrase, casting anxious glances at Hannah, who had yet to move.

"So, uh, Samateur hour, did you really think I wouldn't have a back-up plan?" Metatron's voice issued from deeper in the stacks.

Sam lunged to his feet and began scanning the bookshelves for _Don Quixote_.

"Ah, hello Demon Tablet," he heard Metatron say. _Crap!_

Sam's fingers raced across the spines, past the B's and into the C's. Miguel Cervantes, there! He snatched the book off the shelf and flipped it open. Nestled in the cradle of carved out pages sat a tiny vial glowing with grace. Sam clutched it in his fist, along with the Ark replica, and then scrambled around the other side of the aisle. Painted across several books were a string of sigils, embers smoldering as the spell continued to drain Hannah.

Metatron limped into view at the opposite end, and for a moment they faced each other as though preparing for a duel with supernatural artifacts instead of rapiers.

"And there's Castiel's grace," the ex-angel said with a malicious gleam in his eye.

Shuffling his one hand full of items, Sam took a knife from his back pocket and slashed across three of the sigils. The cinders immediately winked out, and Metatron's mouth quirked ruefully.

"Well, one out of two ain't bad. The Ark you can keep as well. After all, wouldn't want Castiel destroying the world now that I get to go enjoy it." With that, Metatron turned and hobbled hurriedly toward the door.

A moan issued from the other side of the bookcase, and Sam sprinted back around to find Hannah trying to pull herself out from under the fallen unit. He crouched down next to her and helped pull her free.

"You okay?" he asked worriedly.

She gave a clipped nod, then glanced toward the exit Metatron had escaped through.

"We can't worry about that now," Sam said. "We have Cas's grace."

Hannah blinked at the shimmering vial in his hand. "What was the answer to the riddle?"

Sam gripped her hand and hauled her up. "'What's the maddest thing a man can do?'" he repeated, cupping the grace like the lifeline it was. "'Let himself die.'"


	8. Chapter 8: On the Wings of a Prayer

**A/N: This is it. Down to the wire to see if the Winchesters can save the day again. Thanks to a.k.a. T.R who wasn't logged in for the review! =)**

* * *

 **Chapter 8: On the Wings of a Prayer**

Dean's head was ringing and his entire body ached. He wasn't sure whether this was some kind of really bad hangover, or if he'd been hit by a semi. For a prolonged moment, he didn't move, just gradually took stock of his limbs to make sure they were all still connected and in working condition. Static tickled along his skin, but seemed especially concentrated on his forearm.

Dean pried his eyes open and blinked at the floor inches from his face, his cheek pressed against the concrete. Groaning, he brought his arm up to examine it, and blinked some more. Something was off, he could feel it, but he wasn't sure what…

Wait, his arm… Dean jolted upright, his vision darkening as his head throbbed. When it finally cleared, he gaped dumbly at his arm, sans Mark of Cain. And for the first time in a really long while, Dean realized he felt… _normal_. No sinister whispers lurked along the edges of his mind, no minatory hunger for violence and bloodshed pulsed through his veins. He was himself again.

"What the hell…" he muttered.

 _Oh no_. Dean scrabbled to his feet and looked around. This wasn't his room, it was Cas's. They were waiting for Sam to get back with Cas's grace before his borrowed stuff burned up and…

That _stupid_ son-of-a-bitch!

Dean bolted from the room and sprinted through the bunker, ducking his head in each of the rooms. They were all empty. He paused long enough to fish his phone out of his pocket, and frantically hit one of the speed dials.

"Dean, hey, we're on our way back," Sam said after picking up.

"Please tell me you have everything." He stormed into the library. Dean had hoped Cas wouldn't have been in much shape to get very far, but when he came to the war room, he spotted the front door at the top of the balcony wide open.

"Yeah, we got the box and Cas's grace." There was a slight hitch in Sam's voice that Dean didn't have time to address at the moment.

"Well floor it. Cas did something stupid and is about to blow." He barreled up the stairs and outside, spinning around in search of any signs for which way Cas could have gone. Not toward town; Cas wouldn't risk hurting people. Dean scanned the tree line.

"What'd he do?" Sam asked, voice rising an octave.

"What do you think? He removed the Mark! Stupid, self-sacrificing bastard. I'm gonna kill him." Dean spotted some broken branches off to the left, along with what looked like a few splotched scorches on the ground. "Just get here now, Sam," he barked. "Trace my phone when you do; we'll be somewhere in the woods." With that, Dean hung up and broke into an all-out run.

Branches and bushes whipped by him in a blur of green and brown, and Dean momentarily flashed back to Purgatory, when he'd been running through that endless forest searching for Cas. The angel had abandoned him then too, all to 'keep him safe.' But when was the son-of-a-bitch going to learn that Dean only wanted to do the same for him? They were family, dammit! Family stuck together.

Dean skidded to a stop when he caught sight of a glow suffusing through the trees, painting the trunks in a ghostly pale aura. His heart dropped into his stomach. With a final burst of speed, Dean charged into a wide clearing where he found Cas kneeling on the ground, using his angel blade to carve a sigil through the grass around himself. The angel was literally radioactive now, glowing pale blue as grace fizzled from his eyes and mouth.

"Cas!" Dean started forward, but slowed as the static buildup on the air zinged painfully up his spine.

Cas jerked his head up, and even through the glowing eyes, Dean could see his horrified expression. "Dean, no. Go back!"

"What the hell do you think you're doing?" He took another step closer, aware now that he no longer had the Mark to protect him.

"What I have to," Cas ground out, and returned to carving his sigil. With a few more jagged gouges through the earth to connect the lines, he let the blade thunk on the ground, then wrapped both hands around his middle and bowed forward. "Dean, _please_. Go back before you get hurt."

"No! Dammit, Cas, Sam's on his way right now. They have the box and your grace. Why couldn't you just have waited?"

Cas lifted his head with a struggle, and Dean couldn't tell if the blue swirling in his eyes was plasma or unshed tears. "I didn't know if I could hold it long enough, and I didn't want to lose this chance, Dean. Saving you—" He grimaced and curled in on himself tighter. "Saving you, has always been…my mission. Since the moment I laid siege to Hell for your soul. So please, get out of here. I don't want to hurt you."

Another zing scurried up the back of Dean's neck, prickling every hair on his scalp. "Then you'd better keep fighting this!" he shouted back. He noticed that since Cas had completed the sigil on the ground, the growing aura was being reined in, concentrating its energy to that single focal point and angling vertically into the air. When Cas blew, it'd probably look like an alien death ray shooting straight up into the sky.

"Dean," Cas growled. "Why won't you just _go_?"

Dean plowed forward a few more feet, having to stop once again to breathe through the pins and needles starting to vibrate from _within_ his chest. "Look at me!" He waited until Cas painfully lifted his head again, and then took the last step to close the distance, dropping to his knees on the edge of the sigil. "I am not leaving you. Too many times I turned my back on you, Cas. Not this time."

Castiel grunted. "Why must you insist on being noble _now_?"

"Because it's a brother's job to be a pain in the ass."

Cas's face was screwed up in physical pain, but there was also a tempest of emotions behind his eyes: regret, vexation…gratitude, endearment. Dean risked reaching out and gripping his shoulder. A jolt of electricity shot through him, but he gritted his teeth and squeezed.

"Just hang on, just a little longer. We'll defuse you and get your grace back, and you'll be fine."

Cas didn't contradict him, and Dean tried desperately to ignore what they'd already discussed, that Cas may be beyond angelic healing at this point.

Cas made a few more strangled sounds in the back of his throat, and Dean continued to hold onto him, bracing his shoulders against violent spasms as the atmosphere around them grew heavier and more charged. Soon Cas was radiating enough heat to stifle Dean's breathing, but he didn't let go. _Never again_ , he silently promised the angel.

"You can do it, Cas. Breathe." He almost told Cas to pray if it would help, though he didn't know who the angel would address it to. But then, even Dean felt the urge to send a plea out to whomever would listen.

" _Dean!_ " an indistinct voice filtered through the trees.

He craned his neck to look over his shoulder. "Sam?" he shouted.

A moment later, Sam came charging into the clearing, Hannah not far behind. Dean felt a thrill of hope at the golden box and glowing vial in his brother's hands.

"Hurry!" he grunted as another convulsion ripped through Cas.

Sam nearly skidded through the dirt when he dropped down in front of them, and then he fumbled with the box's lid. Gripping the wings of one of the angel figures, he finally managed to wrench it open. "What now?"

Hannah came around behind him. "We have to bleed out the charged grace first."

"Wait, _what?_ " Dean exclaimed.

Hannah's attention drifted toward the angel blade lying on the ground next to Castiel. Sam followed her gaze, and then shot a horrified look at Dean and Cas.

"Wha-we can't…" he sputtered.

"Either do it or run," Cas gasped.

Sam looked like he was going to be sick, his pallor a sheen white in the glare of Castiel's nuclear aura. Dean swallowed back his own surge of bile, knowing that just an hour ago, he could have picked up that blade without a second thought, and the fact that it was Cas might have only given him a moment's hesitation. But he didn't have the Mark anymore, and couldn't stomach the notion of slitting his best friend's throat.

In the end, the decision was taken out of their hands, for Hannah pushed Sam aside and crouched down in front of Cas. One hand took the box from Sam while the other snatched up the angel blade. She spared Castiel a brief apologetic look before swiping the sword across his neck in one fluid motion. Blood didn't even have a chance to spurt out amidst the white-hot grace that erupted like magma.

The blazing energy gushed from Cas's throat in a roar that shook the trees around them. Hannah held the box in front of the stream, and the tumultuous grace poured into it, looking way too large to fit inside its small dimensions. And yet it kept flowing, rattling the sides of the paperweight and Hannah's slim hands as though it could burst out again any second. Dean held his breath, fingers locked in a claw-like grip on Cas's shoulders as the angel shuddered with each pulsing ejection.

Finally the last of it spewed from Cas's neck and slurped into the golden box. Hannah slammed the lid closed.

Cas slumped back against Dean's chest, and in the ensuing silence that had fallen over the forest, his ragged, desperate retching for air sent a jolt of terror through Dean. He shifted his hold, leaning Cas back into his arm, and met the terrified gaze of blue eyes blown wide. Blood was spilling out of the gash now.

"Oh god," Dean choked.

Sam scooted forward, unscrewed the cap of the vial, and tipped it over Cas's gasping lips. A tiny tendril of soft blue light, no more than a candle flame against the inferno they'd just witnessed, snaked into Cas's mouth. Dean didn't know what was supposed to happen when an angel took in grace, but surely there had to be _something_. And yet, Cas's gulps for air were swiftly growing fainter, and the blood had seeped into the collar of his shirt.

Sam exchanged a panicked look with Dean, then glanced helplessly at the empty vial. It hadn't been enough…there'd been such a small amount left over after Metatron's spell, and with Cas taking the Mark off Dean…

"No, dammit!" Dean fisted his hand in the trench coat and lifted Cas a fraction, practically throttling him. "You do not get to do this, you hear me?"

Cas's eyelids drooped to half-mast, the light in those blue orbs dulling.

"Get your ass back here!"

"Dean," Sam's voice cracked, and he tried to extract Cas from Dean's rough grip, but they both ended up clinging to the angel.

Dean shot a scathing look at Hannah, blaming her for being the one to wield the blade, no matter how necessary it was. She didn't even notice the waves of wrath wafting off him though, for her gaze was on Cas, and damn if there weren't tears glistening her eyes.

Even when Heaven had been on their side, _for once_ , what good were prayers in the end?

Dean's vision blurred with hot moisture, first in a gray hue, and then in gold. It grew brighter, stinging his eyes, and he rubbed at them with the back of his sleeve, absently wondering if the fake Ark was about to blow, after everything. But then Sam sucked in a sharp breath and was jostling Cas in Dean's arms.

Dean blinked rapidly until the amber aura coating his sight coalesced into Castiel _glowing_. But not like he'd been when the grace had been going critical; no, this time it suffused his skin with a warm, healthy radiance, amplifying until Cas was almost completely awash in it.

Dean was too stunned to move away, and then he felt _something_ brush across his arm, faint like the tickle of a gossamer web. In the luminescence filling the woods, great black bands suddenly spanned across the trees to his right, arching up behind Cas's limp form cradled in Dean's arms. The oxygen stole from his lungs as he gaped at the flickering shadows of wings.

And in the next instant, they were gone, along with the golden incandescence. Dean looked down and found Cas staring back up at him, blue eyes clear and alert.

"Cas?" he sputtered, not sure whether to believe what he was seeing. There was no trace of blood on the angel's clothes and neck.

Cas slowly rolled his gaze around the clearing, and finally back to Dean. "Well," he said, his normal gravelly voice never sounding so wonderful before. "I believe that was what you'd call, 'cutting it close.'"

A strangled laugh escaped Dean's throat. "You think?"

Sam had broken into a wide grin, and before Dean could think to do it himself, had grasped Cas by the collar and hauled him up into a tight hug. Castiel's arms hovered for an unsure moment, but then he returned the embrace, which Sam held for a moment longer than necessary. Dean wasn't going to make a jibe about chick-flick moments, though, not when their best friend had just more or less come back from the dead.

Sam finally pulled back, and Dean crushed Cas in a fierce hold next. "I thought I told you never to do that again," he growled.

"Sorry."

Dean let out a shuddering breath, and met Sam's beaming gaze. Cas was okay. They were _all_ okay.

Clearing his throat, he released Cas, and then the three of them slowly got up off the ground. Cas turned to Hannah, who had been standing slightly off to the side, mouth set in a pensive line.

"I'm sorry, Castiel," she said, sounding much more anguished than the situation called for.

Cas shook his head. "You did what you had to. _Thank you_ , Hannah."

She seemed to visibly relax at that, and her gaze drifted down to the golden box in her hand. Just by looking at it, one wouldn't be able to tell there was a cosmic nuke inside, just waiting to go off.

"The unstable grace must be dealt with," she pointed out. "This container will not hold it forever."

"Now that I have my wings back, I can take care of it." Cas stepped forward to reach for the box, and stumbled. Both Dean and Sam were on him in an instant, each one gripping an arm to catch him in case he fell.

"Cas?" Sam called worriedly.

He shook his head as though clearing brain fog. "I'm fine."

Dean snorted. "Yeah, you keep using that word, but I don't think it means what you think it means."

Sam quirked a brow at him, while Cas angled a wry look his way.

"My grace is mine again, but…not exactly what I once was," he admitted with consternation.

"I believe that with time, you will regain your full strength," Hannah put in.

Cas's expression pinched as though he wanted to believe her, but didn't want to get his hopes up and be disappointed later. "Even so," he said in his annoying, matter-of-fact habit. "That grace must still be removed from the earth immediately."

"I got that covered, remember?" Dean said, reaching for his phone. He typed a quick message and hit 'send.' Sam was now eyeing him suspiciously, and whatever his brother may have been thinking was soon confirmed when a fifth person joined them in the clearing.

Crowley's shrewd, almost disinterested gaze swept across the sigil carved into the ground. "You rang?"

"We need you to take that—" Dean pointed at the box in Hannah's hands. "Far away. Like to another galaxy."

"What do I look like, your errand boy?"

"You're the one who started all this in the first place," Dean retorted. "Besides, losing half the continental United States to this bomb will be bad for business, right? So can you do it or not?"

Crowley huffed, but held his hand out for the box. Hannah gave him a rather constipated look of mistrust, but Dean cleared his throat pointedly, and she reluctantly passed it to the demon, taking care to hand it off as quick as possible without risking making physical contact.

"Far away, Crowley," Dean reiterated.

The King of Hell scowled. "That's the last time I do a favor for bloody angels!" he snapped before vanishing in a blink.

"Are you sure that was wise?" Cas asked.

Dean shrugged. "I know he's a douchebag, but one thing you can say for Crowley—he does keep his word."

Sam snorted, but didn't respond to that.

Dean took a deep breath, finally able to relax now that Cas was defused and the unstable grace was safely far away. That just left… "Where's Metatron?" They better not have left the dick ex-angel in the Impala alone.

Sam exchanged a guarded look with Hannah, which sent off warning bells in Dean's head. "Um, he got away."

" _What_?"

"With the Demon Tablet."

Dean swore.

"At least he is no longer a threat to Heaven," Hannah said.

"Humanity is still fair game." Dean ran a hand over his head. Well, what was a Winchester Hail Mary win without some kind of complication? As long as none of them were slowly dying or going insane, they were in pretty good shape. So all in all, it was a good day.

"I'll find Metatron," Castiel said, tone gruff with roiling emotion.

" _We'll_ find him," Sam corrected, still lightly holding onto Cas's arm, less to keep the angel steady and more perhaps just to reassure himself that Cas was alive.

"Castiel," Hannah spoke up. "There is still much work to do for Heaven."

Dean's gut clenched; he'd just gotten Cas back. Sam's jaw tightened, and he seemed to squeeze Cas's arm almost subconsciously.

"Can't that stuff wait?" Dean asked.

Cas sighed, casting a torn look between the Winchesters and Hannah. "You and Sam no longer need my help with the Mark. And you can call me if you find Metatron first."

"But…" Sam threw Dean a desperate plea to say something. Why did it have to be up to him though?

"Cas…" A muscle in Dean's jaw ticked in discomfort. He was really bad at this, always had been. But that wasn't going to be an excuse anymore. "Just…stay anyway."

Dean thought maybe there was a glimmer of hope in those blue eyes, that same yearning for something Cas was too afraid to expect. A spiky lump settled in Dean's throat. Why was it easier to say when someone was dying?

"Look," he said, the words catching on his tongue like sandpaper. "We're not asking you to turn your back on Heaven. I get it; that's your home too. But…so is here. With me and Sam."

He could feel Hannah's frown, but Dean kept his gaze locked with Cas's, hoping the angel still had some of that creepy see-right-through-into-your-soul vision. Because he needed Cas to believe him beyond a shadow of doubt.

"Yeah, Cas," Sam echoed softly. "We almost lost you today. Please, just stay for a while."

Some of the tension seemed to drain from Castiel's shoulders, and a soft smile tugged at the corners of his mouth. "Alright," he said, flicking a look at Hannah. Dean thought she would argue, try to convince Cas to leave, but she simply regarded him thoughtfully and finally nodded.

"I…understand now, Castiel." While her expression was not quite tender toward the Winchesters, it was less harsh. "Heaven owes you a great deal for what you've done. You deserve what you have here." With a farewell inclination of her head, she turned and started striding back toward the road.

Dean exchanged a relieved look with Sam, and they both instinctively flanked Cas as they, too, began to make their way back to the bunker. Back home.

* * *

 **A/N: And another happy ending. ^_^ Thank you to everyone who followed, favorited, and reviewed! Huge thanks to 29-pieces-of-me for beta reading as well. Tune in next Friday for the first chapter of my next fic, an even angstier story if you can believe it.**

 **Here's a sneak peek of _Soul Crossed_ -**

"I'm your new God. A better one. So you will bow down and profess your love unto me, your Lord. Or I shall destroy you."

"Cas, come on," Dean pressed. "This isn't you."

Cas's stoic face broke into an uncharacteristic grin then; Cas's smiles were always subtle and slightly awkward, but this was an almost crazed, exhilarated beam. He shook his head in amusement. "That's true. So I suppose there's no reason to keep up the charade anymore." He began to pace casually, and Dean felt a whole new sense of unease. This wasn't right. Cas was always so _still_ , having not perfected human mannerisms even after three years hanging with the Winchesters.

"Who are you?" Dean demanded.


End file.
